Up first is a Fist #20 Adjustable IWB black, see this link for info
This holster has allowed me (5'10" 180lb) to completely conceal a Glock 21 with nothing more than a large button up shirt, but you will need a good belt to hold it snug. I need money so I will let this go for $50 shipping included for the lower 48.
Next up is a Dillon Leather OWB open top holster, brown, put this together with a good belt and it will hold a Glock 21 very tight to your side, you can conceal with very light cover. $50 shipped to the lower 48.
Both of these holsters are made for Glocks without an accessory rail, so they will not fit most 3rd gen models.