For the last couple of months ever since I reviewed A Groats-worth of Grotesques, what the Hell does one do with an alternative OSR Monster Manual?! The thing is that one doesn't feel that one's doing the A Groats-worth of Grotesques by G. Edward Patterson III any justice at my table top.
A Groats-worth of Grotesques has the feel of a real midevil beastry gathered from mages, wizards, naturalists, & other professional classes. The monsters, beasts, & creatures might be perfect for adding from another worldly fantasy plane. And this this plane might be for our game campaign Game Science's Thieves Guild.
This is why they would be unexpected in a campaign setting like Thieves Guild, the players think they know the setting & wham here comes an outre' monsters to strangle or slay your PC's. The fact is A Groats-worth of Grotesques totally out of the box & the player's comfort but be sure not to over due these monsters or the players will soon lose these horror's charm.