Hi The-Erc,

If you are willing to spend 8 HP then I can advise two filters.

1) Well okay LPG then :-) The Make Noise - Optomix with 8 HP not too bad.

2) The Doepfer - A-124 Wasp filter, for a full review report please download the PDF from my below link:

https://garfieldmodular.net/index.php/doepfer/doepfer-a-124-1/

Below 8 HP it's getting seriously difficult, no other filter worth mentioning comes to my mind with less than 8 HP.

Good luck with the search for a good yet small filter and kind regards, Garfield.

For review reports of Eurorack modules, please refer to https://garfieldmodular.net/ for PDF formatted downloads