You can also look out for these contests that are happening habitually:
1.) MAC - once every two months.
2.) NGADM - once every year, during the summer period.
3.) Bosa's contests - once every idunnowhen.
The idea of the MAC, organised by various audio moderators (primarily BrokenDeck), is to have a theme for every contest. The themes can vary from themes that restrict you to certain genres (like the orchestral MAC that's going on right now) and themes that can allow you to do pretty much any genre (like the Christmas MAC we had before).
The NGADM is organised by Echo and I, and is basically a knockout competition during which hundreds of people audiition to enter the competition, 32 or 64 are chosen, and these are paired together in a set of rounds, with the losers of each pairing knocked out until there's one final winner. This one doesn't focus on set themes/genres and anyone can join.
Bosa also occasionally organises contests with ambitious names and themes like Quest for the Crown and Dreams of Splendor. This is the only kind of recent contest that happened more than once which offers real money as prizes and not store credit, all out of Bosa's pocket, so if he organises another one in the future, it'll be worth looking into.
Those are the three "main" ones that are going on right now. And if you keep an eye on the forums you might find other contests happening. Just make sure you keep active and take the opportunity when it comes.