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>Mainly looking for pics that clearly show glutes, quads, hamstrings, calves, hip flexors.
Seriously you need to just google it and just look at images and print them out.
If you want something to pin on the wall that looks official and laminated: https://www.anatomywarehouse.com/the-muscular-system-anatomical-chart-a-102597
For a 3D interactive thing, there are many apps like "visual anatomy free" (android) and anatronica (android app or try their flash version if you still have flash installed