Asked on our Slack channel:

I believe the simple solution is to add Tennis/racquetball/squash to the list... but a feature that would cover this and more (i.e. Roller Derby ) would to have a Custom Sport option.

Same as the other leagues but also include the option to upload

bugcat has been making some nice coats of arms that would work well as symbolic trophies for leagues or tournaments. See #off-topic channel on Discord. To make use of this sort of thing we would need a way for people to proudly display the trophies they have won - maybe on their OSR profile page?