Hereby the betting blogs and websites that I visit regularly and wholeheartedly recommend:

Sports Arbitrage & Value Betting Services:
RebelBetting: Sports Arbitrage and Value Betting software
BetBurger: : Sports Arbitrage and Value Betting software
Trademate Sports: Technical value betting platform covering sharp books as well

Value Betting Services:
WinnerOdds: A machine learning algorithm looking for value on the tennis markets
Mercurius Tradr: A machine learning algorithm looking for value on the football markets

Betting Brokers
Sportmarket: The only broker I currently use. Great reliability, customer service and offering as far as my experience goes
AsianConnect88: An alternative to Sportmarket, which seems to have a solid reputation

P&L:
Daily25: Steve runs the only P&L betting blog that I am aware of. He also writes about his other activities, including startup investing, Bitcoin and the stock market. Overall a very interesting read.

Betting Strategies:
Green All Over: Cassini is the veteran of sports betting and Green All Over is possibly the longest standing betting blog out there. Great resource for various strategies, especially in the field of American sports
Betaminic
Punter2Pro: Toby’s blog is very similar to mine and covers profitable betting strategies and reviews of various services
SportsBettingQuant: Toni is backtesting famous betting strategies and building bots

Tipsters:
GodsofOdds: A relatively new tipster platform, which is one of the very few publishing closing line data on its tipsters
pyckio: A tipster platform, which is charging you pro tip as opposed to a fixed period fee. I don’t follow their advice, but find the concept interesting.
Secret Betting Club: Website reviewing tipsters with quite a long history

Trading:
Betfair Pro Trader: Probably the best blog on the web for Betfair bots. The guy has written a few books on the topic as well, you can check them on the website.
Smart Sports Trader: A newer blog on automated betting strategies.

Odds & Stats:
Oracle’s Elexir: For League of Legends data in downloadable format. Tim collects LoL data in great detail, does some great analysis on his blog, is doing analytical work for Fnatic and is involved with the LoL fantasy project esportsone.com
gol.gg: For League of Legends data – also a main source of Oracle’s Elexir
Football Data: Joseph Buchdahl’s website for football data in downloadable format
Tennis Data: Joseph Buchdahl’s website for tennis data in downloadable format
BetBrain: Main source for above two, better for the tech savvy users)
BetGPS: Free tool for betting analysis, works well with Football Data listed above. Haven’t had the chance to test all its capabilities so far, looks quite cool though
WhoScored: Football stats
SoccerVista: Football stats
Soccerway: Football stats
Soccer Stats: : Football stats
OddsPortal: Odds data

Bookmaker Reviews:
SBR: They can also help you if a bookmaker is not paying you, an institution in the betting space really
Top 100 Bookmakers
Arbusers

Gambling News:
CalvinAyre
Gambling Insider

Betting Blogs:
Cognitive Football
Betting is Cool
QuantumSports
Sam Priestley