UTG
The $20 Picatinny riser, in 0.5", 0.75", 0.83", and 1.0" saddle heights and 3 or 13 slot lengths.

This is the plainest form a Picatinny riser takes: a slab of aluminum that lifts a rail-mounted optic an inch off the receiver so the sight picture stops feeling like a chin weld. The UTG Super Slim does that for about twenty dollars and does not pretend to do anything else.
Four saddle heights are offered, 0.5, 0.75, 0.83, and 1.0 inch, each in a 3-slot and a 13-slot length. The 0.83 inch 3-slot weighs under an ounce. Construction is 6061-T6 with a matte anodized finish, and the mount uses locking Torx screws with square integral recoil stops that index into the rail slots so it does not walk under recoil.
The honest limits: this is a riser, not a mount, so it raises an optic that already has its own base and it will not accept a bare Aimpoint Micro. And a $20 riser under a $600 optic is a false economy on a rifle that gets hard use. On a range gun, a .22 trainer, or a budget build, it is exactly the right amount of hardware.

Smith & Wesson
Smith & Wesson M&P15 Sport III
1 shared compatibility tags

Sig Sauer
Sig Sauer M400 Tread
1 shared compatibility tags

Sig Sauer
Sig Sauer M400 Forge
1 shared compatibility tags

Palmetto State Armory
PSA Sabre-15 M4A1 14.5" CHF Quad Rail
1 shared compatibility tags

Radical Firearms
Radical Firearms RF-15 16" (15" RPR)
1 shared compatibility tags

Foxtrot Mike Products
Foxtrot Mike Mike-9 Ambi 16" Front Charge Rifle
1 shared compatibility tags
Add the UTG Pro Super Slim Picatinny Riser Mount to your build and see how it enhances your platform.