With GM's Aid III: Monster Knowledge Cards Volume I - Aboleth to Fungus your job as GM just got easier. There is a card for each of the OGL monsters from Aboleth to Fungus in the SRD and each includes a number of facts about that particular creature. Each fact is tied to an increasingly higher Knowledge check DC. When the players characters are faced with a creature, whip out the appropriate card, have the players make rolls, and then consult the card to tell them what they know.
The cards have been formatted to print on any standard-size business card paper, or you can just print them on cardstock and cut them out using the lines as guides.
Coming soon - GM's Aid IV: Monster Knowledge Cards Volume 2 - Gargoyle to Owlbear!