Bestiary completion

I found this in a tropical island map, trapped inside an essence. I have all the bestiary passives but a few changes would help, like removing the notable that gives a chance for yellow beasts to be replaced with red, and only taking the notable that gives increased chance for beasts from the caverns, I had the caverns as well as the deep. There is also the Natural Selection notable that makes the beasst more likely to be less common types, but who knows which beasts are considered to be common type. Unfortunately I think you're going to have to grind this out in maps and be at the mercy of RNG.

Summary for everyone who is looking forward to waste precious life time for a pointless challenge like me :).

Yellow Beasts:
You can target farm certain yellow beasts in the campaign. For that you can look up the location of the particular beast on https://poedb.tw/us/. You can reset an instance by clicking+Strg on the waypoint of the campaign screen or the entrance to the area. Spam instances until you hit a map with Einhar. You need only around 1-5 Einhars to find particular beasts in the campaign because the pool of beasts that can spawn is very small.
If there is no location noted for a beasts on poedb.tw (or The Eternal Laboratory which is a bug) that means you can only farm it in maps. Unfortunately these beasts need a lot of grinding because there are around 170 in the pool and they don't seem to be weighted. It took me more than 100 maps to find the last yellow beast.

Red Beasts:
You can influence the spawn rate of red beasts by the nodes on the atlas tree. The nodes begin with " The Hunt for...". There are also nodes which convert yellow to red beasts so you might want to use them if you have already found all yellow beasts. You need to spawn the 4 bosses by beastcrafting in your menagerie. You can find the harvest beasts by running einhars memories of harvest beasts. They are very expensive so you may want to run them with your friends to reduce costs if you don't hit the jackpot beasts.

Have fun!