Although not fully completed, here's my DIY convertible 6 Speed/Sequential shifter. Description and plans in comments : r/simracing
DIY Sequential Shifter using Suzo Happ and Pro Micro | RaceDepartment
DIY - Sequential shifter with button box
Amazon.com: aikeec USB Sequential Shifter PC Gearshfiter Windows for Logitech G25 G27 G29 G920 TH8A Sim Racing Wheel Fit for Dirt WRC Assetto Corsa LFS ETS Forza Horizon 4 PC win10 win7
Simracing DIY Sequential Shifter - IDW
Showroom - DIY Sequential Shifter
DIY Racing Sim Sequential Shifter by BeavisMotorsport | Download free STL model | Printables.com