In the game, you often will get way more Energetic Blood Plasma than you need, even before you get the ability to produce it yourself. Since selling creature corpses and live creatures are a good way to make money, I took some time to figure out what are the best monsters to extract blood plasma from, and the best ones to sell. The following table gives the opportunity cost per unit of blood plasma, taking into account the cost of the material (versus just selling it), the project cost (usually low), and labor cost (also very low), along with what extra stuff is produced (i.e. zombie parasites).
The gist of it is that Zombies, both alive and dead, are usually good for extraction, mainly because you can sell the parasites that are produced. In the early game, you're also likely to encounter the following good candidates: Bullfrogs (though you might want some to make muskets), Spikeboars (same, but with Quillbows), Shamblers, and Mongorns.
On the flip side, anything that requires multiple corpses like rats and such are very expensive per unit, and it's usually best to sell those. Also note: anything with a * below has alternate uses or other products that you should also take into account. (I didn't count zombie parasites though).
Blood Plasma: Megazombie Corpse 2620
Blood Plasma: Zombie Boomer Corpse 3700
Blood Plasma: Zombie Corpse 4100
Blood Plasma: Fat Zombie Corpse 4360
Blood Plasma: Bullfrog Corpse* 5380
Blood Plasma: Living Battered Zombie Trooper 6073.333333
Blood Plasma: Chryssalid Corpse 6100
Blood Plasma: Living Zombie 6300
Blood Plasma: Living Megazombie 6733.333333
Blood Plasma: Spikeboar Corpse* 6940
Blood Plasma: Living Female Tomb Guard 7203.333333
Blood Plasma: Living Male Tomb Guard 7203.333333
Blood Plasma: Living Fat Zombie 7740
Blood Plasma: Shambler Corpse 7940
Blood Plasma: Living Zombie Infector 8305
Blood Plasma: Strix Corpse 8332.5
Blood Plasma: Living Strix 8905.714286
Blood Plasma: Living Shambler 8970
Blood Plasma: Living Giant Bombardier Beetle 9180
Blood Plasma: Zombie Infector Corpse 9360
Blood Plasma: Mongorn Corpse* 9750
Blood Plasma: Living Chryssalid* 10062.5
Blood Plasma: Living Spikeboar 10220
Blood Plasma: Living Bullfrog 10253.33333
Blood Plasma: Reaper Corpse 10333.33333
Blood Plasma: Living Giant Rat* 10490
Blood Plasma: Living Fenrir 10920
Blood Plasma: Tomb Guard Corpse 11013.33333
Blood Plasma: Living Giant Beetle 12360
Blood Plasma: Fenrir Corpse 12380
Blood Plasma: Living Reaper 15166.66667
Blood Plasma: Living Mongorn 15375
Blood Plasma: Owlman Corpse 15880
Blood Plasma: Werecat Corpse 15880
Blood Plasma: Werewolf Corpse 15880
Blood Plasma: Living Owlman 17940
Blood Plasma: Living Werecat 17940
Blood Plasma: Living Werewolf 17940
Blood Plasma: Zombie Trooper Corpse 18100
Blood Plasma: Living Megascorpion 20460
Blood Plasma: Living Zombie Boomer 20500
Blood Plasma: Giant Beetle Corpses 21020
Blood Plasma: Giant Rat Corpses 21300
Blood Plasma: Megascorpion Corpses 22500
Blood Plasma: Living Black Werecat 22940
Blood Plasma: Living White Werewolf 22940
Blood Plasma: Living Shadowbat* 25560
Blood Plasma: Living Chupacabra* 30460
Blood Plasma: Chupacabra Corpses 31500
Blood Plasma: Shadowbat Corpses 49800
