HGLRC Zeus350mW VTX 5V M2 M3 16x16 20x20 25.5x25.5 5.8GHz VTX Betaflight for FPV Racing Drone Quad (SMA)

I would probably use the HGLRC Zeus 350mW which is my standard for pretty much all builds. I even have one on a 35 mm propped tiny freestyle. I have also used those triangle whoop specific VTXs such as the GEPRC Rad Whoop VTX. Both of these will mount directly onto the 25.5 x 25.5 whoop mounting pattern. You might need longer bolts or screws.