We have been selling hard spacers for over 20 years. In Europe this is the standard. The 1/16" are solid. The 1/8", 3/16" and 1/4" are perforated to let the thin set through.
There are Regular, Long and T Type.
Flex Tile Spacers
Hard Plastic Spacers
Gong Brush with Long Handle / BR-G-L
Lippage Eliminator / DT-LE