I think I found the best filters for my bettas! I was using sponge filters. But the air pumps were really loud. So I found these 5-10gallon clear HOB for $10.00 a piece.
So far they are amazing! Very quiet, small. They don't take up as much room as you'd think they would. Comes with a sponge to put on your intake tube. I just recommend buying more sponge media because there is a lot of room in the filter that could use more media.
P.s you can turn the flow up or down on the filter too so it's not that strong for them.