OpenBuilds 6020 Rail X axis Belt driven with Belt Adjustment.
Using Nema17 motor and GT2 Belt with 20 tooth idler and drive gears.
Just updated the parts with more clearance and added strength.
Added: X_carriage_Belt tensioner_10mm.stl is a stronger part and has options for tensioner bolt. You can either use 4mm Cap head with a lock nut or Hex head bolt
The is technically a remix from DoctorBaf but changed it significantly but his excellent ideas are there.