@HGTV Soapboxfan So I don't know if you are familiar with tag fighters, but your goal is to fit a character in a point/mid/anchor role. Point is your starter, operates really strong out the gate but does better with assists. Mid would have a great assist but maybe stronger with an assist like the point character. Your anchor is your last resort character, one who does REALLY well solo and can help you close out a match once you are down.
So Android 21 is great, because I'd argue she can fit into any of these roles. To keep it simple, let's make her point. So for your mid/anchor, a good fit is any character with a beam assist: an assist attack that is a beam that goes across the screen. They are great at full screen pressure and still help you combo. So you'd be looking at:
Goku Black, SSJ Goku, Tien, Gotenks, and some other characters I'm forgetting I'm sure. Android 21 (if you want to move her), Bardock, Yamcha and Vegeta also sort of fill this archetype, their assists function similarly to beams.
So for an anchor, this might not necessarily be the character that is "the best". It could also be the character you do the best with. If you maintain your sparking (the red power up thing), it's going to be hella strong for this final character, so you want it to be somebody you know you personally can do damage with. But in general, Android 16, Cell, Adult Gohan, Bardock, Tien, any Goku and any Vegeta are pretty decent in this slot.
Another good thing about tag games is you do have some flexibility in who you play. For example, I enjoy playing Frieza, who isn't that great comparatively. But my two other characters, Black and 21, can make up for his faults because they do really well in the roles they play for my team.
Bare in mind, this is all info based on the old patch, but most of it should be good. It might help if you check out the combo trials and see what characters feel good to you.
