Hey there, discovered this really useful/cool list of tools someone compiled from Reddit, thought I'd share it here for everyone else to use as well. :)
Game companions (1-3)
Pre-game analysis & counterpick tools (4-7)
Stats sites (8-13)
Champion stats & builds sites (14-23)
International summoner stats sites (24-27)
Sites for learning League (28-35)
Replay & spectating watching tools (36-41)
Skill tests (42-44)
Coaching & mentoring (45-47)
Other sites & tools (48-56)
Esports stats, news, & portals (57-68)
Official Riot sites & tools (69-78)
1. [Mobalytics](https://mobalytics.gg/) - A game companion that helps players define their strengths, eliminate weaknesses, and provides them with personalized advice on how to improve.
2. [Blitz.gg](https://blitz.gg/) - A desktop app that allows you to prepare for a game during champ select and learn from your performance once a match is over.
3. [LoLSumo](https://lolsumo.com/) - A smartphone app that gives you pre-game analysis, intel, and advice on the upcoming game and situational item build suggestions
Pre-game analysis & counterpick tools
4. [LoLWiz](http://lolwiz.gg/) - An Overwolf app that gives useful information about runes, builds, and matchups, before and during a match.
5. [LoL Counter](https://lolcounter.com/) - An excellent place to go for champion counter picking information.
6. [CounterStats](https://www.counterstats.net/) - A very clean interface on this well-made tool makes it a great place to learn champ counterpicks.
7. [Porofessor](https://porofessor.gg/) - Want to learn everything you can about live games? You can see summoner stats for ranked (solo/flex) and norms (draft/blind) with Porofessor.
8. [OP.GG](http://na.op.gg/) - Still one of the best League of Legends stats websites out there. Player/champion data, spectate pro matches, and see leaderboards.
9. [League of Graphs](https://www.leagueofgraphs.com/) - A very cool stats site with lots of data visualization for warding, summoner spell win rates, pro game info and much more.
10. [Poro Laboratories](https://na.poroscience.com/) - A summoner stats site dedicated to keeping track of individual achievements and records.
11. [Quickfind](http://quickfind.kassad.in/) - Detailed stats for every game, win/loss for placement matches, free champion rotation for all servers, and ranked LP decay.
12. [LoLProfiler](https://lolprofile.net/) - Analyzes your score and can compare your performance to the performance of specific summoners. Radar diagram shows your performance on warding, objective control and more.
13. [ChampionMasteryLookup ](https://championmasterylookup.derpthemeus.com/)- The site’s name speaks for itself, track your own or anyone else’s mastery level and progression.
Champion stats/builds sites
14. [Champion.gg ](https://champion.gg/)- Detailed information on which champions are performing well in current and previous patches. The site gives counter pick info in addition to win rates for skill builds, runes, masteries and more.
15. [U.gg](https://u.gg/) - Useful tool for finding the best champs and builds for for every role and ranked tier. One of the most notable newcomers since last post.
16. [Pro Builds](https://www.probuilds.net/) - See what builds the pros are using for different champions and gain inspiration on your item sets.
17. [LoLalytics](https://lolalytics.com/ranked/worldwide/platinum/plus/home/) - Learn almost anything about a champion from their counters to most successful items, skill orders, and runes.
18. [RuneForge](https://runeforge.gg/) - Gives recommended rune builds for every champion with explanations for why each rune is good for them.
19. [Legendary Builds](https://www.overwolf.com/app/Colorfulstan-Legendary_Builds) - Found this in the Overwolf store, looks pretty decent.
20. [METAsrc](https://www.metasrc.com/5v5) - Updates every patch with analysis for champion statistics, counters, synergies, and builds.
21. [LoLRift](https://www.lolrift.com/home) - Search for champion stats in every region and tier. Includes ability clips and even lore for reference.
22. [KoreanBuilds](https://koreanbuilds.net/) - Want to know what your Korean high-elo counterpart is building? This is the site for you.
23. [LoLMasters](http://lolmasters.net/diamond/index) - A decent website with very cool meta analysis tool that shows champion play rates per lane.
International stats sites
24. [IPLLOL](http://iplol.co.kr/) - Korean stats website.
25. [FOW.KR](http://fow.kr/) - Korean stats website.
26. [SalsaLoL](https://www.salsalol.com/) - Spanish stats website.
27. [Teemo.gg](https://teemo.gg/) - A very clean statistics website available in English, Spanish or Portuguese.
Sites for learning League
28. [ProGuides](https://www.proguides.com/) - This is another paid service but the guides here are among the best on the Internet. These kinds of sites are worthwhile if you’re willing to invest the time in studying.
29. [Skill-Capped ](https://www.skill-capped.com/)- Very detailed video guides from top-tier players, organized and structured for a very effective learning experience.
30. [Surrender@20](http://www.surrenderat20.net/) - One of the best ways to stay up-to-date with game announcements including new skin releases, patches, client updates, and more.
31. [Mobafire](https://www.mobafire.com/) - Some of the best player-created League of Legends guides on the internet, many of which go into individual champions in great detail, some even written by players up to Challenger tier.
32. [League Wikia](https://leagueoflegends.fandom.com/wiki/League_of_Legends_Wiki) - The most detailed source of League of Legends information you could possibly hope for.
33. [Summoner School ](https://www.reddit.com/r/summonerschool/?utm_source=reddit&utm_medium=usertext&utm_name=leagueoflegends&utm_content=t3_aje8it)- An essential subreddit for anyone learning the game. Great community and often very insightful posts.
34. [NerfPlz](https://www.nerfplz.com/) - These guys have great info on current meta, patch note breakdowns and an excellent blog that’s educational and entertaining.
35. [MoreLegends](https://morelegends.com/en) - Learn and improve with curated video guides and in-game quests.
Replay & spectating tools
36. [Tracking the pros ](https://www.trackingthepros.com/)- Really cool site for watching pro games, it really shines around Worlds when all the pros are in a server and playing against each other.
37. [Aof.gg](https://aof.gg/) - An excellent downloadable replay client that will automatically record all your games.
38. [Plays.tv](https://plays.tv/) - Records replays locally as a video file and timestamps events such as kills, deaths and assists. Less detail available than client native replays, but it’s an excellent tool and saves time.
39. [Replay Hud](https://www.overwolf.com/app/Overwolf-Replay_HUD) - Replay tool available through Overwolf. Has helpful hotkeys for capturing specific recordings.
40. [LoLSpectator](https://lolspectator.tv/) - If you know the name of the summoner you want to spectate, check out this website. It lets you watch anyone’s games.
41. [LoLStreamBrowser](https://chrome.google.com/webstore/detail/lol-stream-browser/edidfaijmhpefkbnobdcepampbncgejp?hl=en) - An extension for Google Chrome that lets you browse LoL live streams and receive notifications for your favorites when they go online.
42. [Mobalytics Proving Ground](https://pg.mobalytics.gg/) - Refine and test your mechanical skills in a way that simulates League of Legends.
43. [ROGArena.com](https://rogarena.com/training/) - A cool training portal from Republic of Gamers for speed, accuracy and more.
44. [Smiterino ](http://smiterino.com/)- Test your smiting ability in different scenarios and Smite damages.
Coaching & mentoring
45. [LoL Training House](http://loltraininghouse.com/cgi-bin/Home.py) - A great place to partner up with LoL coaches or find mentees.
46. [Gamer Sensei](https://www.gamersensei.com/senseis/searches?sort_by=relevance&game=league-of-legends&page=1) - One of the most well-known coaching sites in all of gaming.
47. [XsollaAcademy ](https://xsolla.academy/game/lol/)- Another option to find a coach for any role and tier.
Other sites and tools
48. [Zeal.gg](https://zeal.gg/) - Track your daily progress against other summoners like your own leaderboard.
49. [Riftkit](https://riftkit.net/) - Great tool that allows for training and planning by moving markers around the Rift. Share a session with friends or teammates to discuss strategy or teach the game.
50. [Ultimate Bravery](https://www.ultimate-bravery.net/) - Let RNGesus take the wheel in choosing your champion and build next match. Please only use in norms... =)
51. [2ez.gg](http://2ez.gg/) - Aggregates multiple League of Legends sites (including the subreddit) and puts them all in one place. Pretty convenient.
52. [Wasted on LoL](https://wol.gg/) - If you’re wondering how much time you’ve invested in League of Legends, enter your summoner name into this site.
53. [LoL Inactive](http://www.lolinactive.com/) - This website is for anyone looking for a particular summoner name and wants to check when it becomes active.
54. [LoL Item Set Generator](https://lol-item-sets-generator.org/) - A tool that lets you download item builds that are based on win rates.
55. [League of Designs](http://leagueofdesigns.net/) - Compiles all discussion of a champion from Riot side. Great tool for people that want to keep up with their favorite champ’s upcoming changes.
56. [What Is My MMR ](https://na.whatismymmr.com/)- Find out your MMR quickly based on your recent matches you played solo.
Esports stats, news & portals
57. [GamesofLegends](http://www.gamesoflegends.com/esports/home/) - An incredibly in-depth site for keeping track of statistics across pro Leagues around the world.
58. [TheScoreEsports](https://www.thescoreesports.com/home) - Keep up with eSports news and scores. They make informative documentary videos as well.
59. [Gamepedia](https://lol.gamepedia.com/League_of_Legends_Esports_Wiki) - A very up-to-date LoL eSports Wiki - one of the best ways to keep up with split results and team roster histories.
60. [GosuGamers](https://www.gosugamers.net/) - News, stats and team information from the League of Legends professional scene.
61. [Dexerto](https://www.dexerto.com/) - eSports news that’s available in English, German, Italian, French, and Spanish.
62. [LiquidLegends](https://www.liquidlegends.net/) - Team Liquid’s LoL portal contains news, excellent inside information on the pro scene and an active forum.
63. [Summoners-Inn.de](https://www.summoners-inn.de/de/start) - A regularly updated pro LoL news site based in Germany.
64. [Fragbite.se](https://fragbite.se/) - eSports news site based in Sweden.
65. [eSportspedia](https://lol.esportspedia.com/Main_Page) - A news website with lots of content on the current goings-on in the LCS and other pro League tournaments.
66. [LoLeventVoDs ](https://www.reddit.com/r/LoLeventVoDs/?utm_source=reddit&utm_medium=usertext&utm_name=leagueoflegends&utm_content=t3_aje8it)- Your go-to place to catch up on the games you’ve missed. The vods are conveniently listed with the game start time to save you scrolling through to find the action.
67. [Abios Gaming](https://abiosgaming.com/) - A great interface on both the website and chrome extension for keeping up-to-date with, and receive notifications for, League of Legends pro games.
68. [Strafe](https://www.strafe.com/) - A mobile esports app, great way to keep track of scores quickly and on the go.
Official Riot sites and tools
69. [League of Legends](https://na.leagueoflegends.com/en/) - Riot’s official website.
70. [Riot e-Sports](https://nexus.leagueoflegends.com/en-us/esports/) - Riot’s official e-Sports site has all the latest information on the pro games as well as excellent stats for most leagues.
71. [LoL YouTube](https://www.youtube.com/user/RiotGamesInc) - Riot’s official YouTube.
72. [LoL Support](https://support.riotgames.com/hc/en-us) - Riot’s official customer support site.
73. [LoLeSports YouTube](https://www.youtube.com/user/LoLChampSeries) - Riot’s official eSports YouTube.
74. [LoL Esports Official site](https://nexus.leagueoflegends.com/en-us/esports/) - Riot’s official eSports website.
75. [Riot API for developers](https://developer.riotgames.com/) - Riot’s official API & developer portal.
76. [LoL Match History](https://matchhistory.na.leagueoflegends.com/en/) - Riot’s official match history data.
77. [LoL Message Boards](https://boards.na.leagueoflegends.com/en/) - Riot’s official message boards.
78. [LoL Account Privacy Info](https://support.riotgames.com/hc/en-us/requests/new?ticket_form_id=38164) - Discover how much money you’ve wasted invested wisely in League of Legends and other game-related statistics.