It would be nice to be able to filter by additional criteria, like language and card condition. For example, I distinguish between paper cards and online cards using the card condition field: for paper I use near mint, for online I use mint. Other players may use this field to distinguish between different collections. It is a rather simple feature that could help a lot of users.

PS. How do I delete the post? I just found out about the Support & Feedback button! Sorry :/.