As this pic，we can use some Limit rules to selecte Maps。
For example i want to practice DT，i will limit BPM in 100~150，and ar=8 
Or i want to play Key=4 status=rank
Or sometimes i want to practice my Hand speed，i will enter ：bpm>200 key=4(and so on） or bpm>200 stream
and in some time when i just eat satisfied，i may enter: nanahira or yuikonnu or victorica_db or mod=mania star<4 ( For relax
But entering these keywords is not convenient，and sometimes，il forget how to spell smoe mapper’s ID，or some singer‘s name、、、
so i think，we can add a Key words save button Beside Group and Sort bottom。