If you are using datagrid 2(https://docs.mendix.com/appstore/modules/data-grid-2/) , then drop down filter can be added.
If custom search has been implemented, If the association is 1-1 or 1-* try reference selector(https://docs.mendix.com/refguide/reference-selector/) or if the association is *-*, try Reference set selector (https://docs.mendix.com/refguide/reference-set-selector/)
Hope it helps!!!
You can use a Datgrid2.
Its very easy to use and have much more Features.
After adding the datagrid2, search in the tooobox for Filters. You will find Filters dir Strings, Datumfilter, dropdown Filters etc.
Hope it helps