You don't need to subscribe, but I do as its easier to keep track of the SubReddits.
Here are the Links to the Sub Reddits for sports streaming, at least the ones I have bookmarked, you may not use them all as I'm not sure if you follows all these sports, because even I don't, I just have friends over sometimes and they ask if I can put something on:
https://www.reddit.com/r/nbastreams/
https://www.reddit.com/r/MLBStreams/
https://www.reddit.com/r/ncaaBBallStreams/
https://www.reddit.com/r/CFBStreams/
https://www.reddit.com/r/nflstreams/
https://www.reddit.com/r/BoxingStreams/
https://www.reddit.com/r/MMASTREAMZ
https://www.reddit.com/r/NHLStreams/
https://www.reddit.com/r/redsoccer/
The way it works is pretty easily, basically you would head to the Sub of the sport you want to watch, click the game thread and look for a stream that works on your device. The way reddit works it the best streams are usually on the top, as they get up voted by other users. The most reliable as Thunder mentioned is BuffStreamz, I actually used them to stream the UFC Fights, Nuggets/Spurs and the Astros/Mariners game last night on three different devices.
For example, say you wanted to watch Jazz/Rockets right now you'd head to NBA Streams, click this game thread
https://www.reddit.com/r/nbastreams/...ets_930_pm_et/
And on the top will be the list of the verified best streams.
What you stream it on would depend on the technology you have. I have an Xbox, so I usually just use the web browser on the Xbox, click a stream and it plays on my TV through the Xbox. I also sometimes stream on my Laptop, Ipad and phone and never have any issues. Its been a huge benefit. I don't pay for cable, don't need MLB TV, and don't need an NBA/NFL Package to watch games I want.
Only thing is, I would advise to be careful of which streams you click, some of them are by spammers who post sketchy sites with ads and potential harmful shit. My computer is heavily protected (I major in Cyber Security) so I can't even open the sketchy sites without my MalwareBytes shutting that shit down, but for normal computers it could be harmful.