My design is specifically created for 90x15mm fan, that is a popular PC format and can be find very easilly for a good price. For example I’m using with a Thermalright TL-9015B, that can be purchased with next days shipping for around 9€. Can be mounted with a FAN filter, but just the kynd of filter without plastic frame will fit.
What size do you have in mind? 90x25?