Video1 | Design Selection & Tradeoffs
www.rcpowers.com
http://rc-plans.com/
https://aerofred.com/
https://outerzone.co.uk/
https://www.titandynamics.org/3dhangar
Titan Dynamics is Paid but you can mimic the designs. As details are documented on there site.
(Look at the Titan Hammerhead, a difficult one to make but innovative)
You can search the web for other websites