You can manage & track your card collection and decks once you create an account and login.
You & your friends can play with any cards you want. At this stage in the game's (after)life, if you're meeting up with people to play then you already know eachother and know what sets you're all using. Have fun, that's what matters. Anything said in this document has no bearing on what you & your friends do. This is referring to what the broader community is using for both casual and organized play.
When WotC canceled the Transformers TCG in 2020, multiple groups formed within the community with the desire to continue the game. There was a lot of talk on which groups "matter" and which are "official". It can be a bit confusing, even if you're pretty active in the community. This is an attempt to clear things up, especially for those who are new or just returning to the game.
It sounds like an obvious thing to say, but community sets are sets of cards made by groups within the community. I like to use the term "community set" rather than "homemade" or "fanbrew" because it emphasis that these cards are made by well known groups within the community, and not by a single person who created ten cards last night. Community sets are designed and tested for months by many people who know the game extremely well, much like official WotC product was. Many of these designers are tournament champions and/or have decades of experience playing card games. Progress and testing is usually made public, making it easier for the community to trust that the cards are well balanced. Most importantly, they're designed with the game's best interest at heart, and not simply "wouldn't it be cool if..."
To put it simply, this game will not thrive without new cards. WotC left us in a precarious situation with Wave 5. It was a very powerful set of cards, and clearly not how the designers would have ended the game. This game was not designed as a deck builder with a static set of cards, it was designed as a growing TCG. Without new cards, the game will eventually devolve to a very limited number of strategies/decks.
In addition to all that, new cards simply bring excitement. Having something new leads to further engagement. People who quit come back to see what's been happening and what's new. That is extremely important for a small community like ours that no longer has outside marketing.
This argument used to come up a lot. People have been making up cards since the game first launched, but the vast majority of players just never used them. There's never been anything to stop a group of friends from using their own set, and there's nothing stopping that from happening now. In the same vein, many fan-made cards now will see little to no play within the broader community; just because someone shares their new set on Facebook doesn't mean the community is going to adopt it. And that's okay! As was stated at the beginning of this, your group of friends can play with whatever they want.
This game has now been "canceled" and in the hands of the community longer than it was ran by Wizards of the Coast. In that time, a development team has naturally grown and come together. Colloquially known as Allied Crossplay, this team has been working together since 2020 to further develop the game while trying to stay true to WotC's vision. They maintain a casual-friendly environment while foussing on Transformers mythos almost as much as gameplay.
What was stopping WotC from making such a card? Perhaps you've heard of Peace Through Tyranny? Daring Escape? Press The Advantage? Inevitably, very powerful cards will get made. It happens to professional companies even. However, the team will not intentionally add a game-breaking card for the same reason WotC wouldn't either: they want the game to prosper. This goes back to the importance of being public about how thoroughly cards are tested, and by who. There's a big difference between having dedicated people with years of experience testing cards, versus people who play casually with friends on the weekend.
We will never have "official" sets again, but these are as close as it gets.
Instructions for that are right here
There's a guide for that