Welcome!
Nymphs are one of the rarest cards in the game. You can only get them from the oracle or winning tournaments.
Tournaments are fun. As long as there are at least 8 people, the tournaments are single elimination, but still take a bit to play. If you win the whole tournament it might take you a couple hours of your time. There is 1 tournament every week, and you can look at the tournament section on the forums to find the dates and times. I like tournaments because a.) you can win a mark/nymph code to get a super rare card if you get 1st place and b.) every week there is a different ruleset that restricts what cards you can use in the tournament. This keeps the meta fresh and makes the tournaments less up to chance. If every single card was allowed, every tournament would just be a roll of the dice, because there is no deck in this game that can beat every other deck. There isn't even a deck that comes close to losing to only one other deck. Everything has counters.
There's a lot of fun things to do. Look at the different forum sections. There are card art competitions, card idea competitions, PvP Events that have their own ruleset and often last several weeks as opposed to a 1 day tournament. There are forum games (mafia is about to start up soon under the forum games subsection). People are also often in chat. There is also league, which lasts about 3 months and lets you play as much or as little as you want with other people to climb up an ELO ladder system. The top players in that ladder get rewards at the end too.
False gods are not worth farming. Farm arena.
Open ETG is good but needs some visual work. Players might move there when flash support cuts off. 1.4 is never coming out because the developer disappeared like 7 years ago. Current version is fine and meta gets switched up through using specific rules. The only truly OP card in the game is dusk mantle.