There are plenty of options for all the trials but here is what I did for mine:
Trial 1045: Undead - Catastrophe x200
Eldime Necropolis S and Present has a ***ton of Skeles that are fairly easy to kill.
Trial 1046: Aquans - Catastrophe killing blow x200
Didn't have any problems in Kuftal Tunnel off of Robber Crabs, another great spot is Vunkrel Islet S with the Crabs/Pugils.
Trial 1854: Lizards - Catastrophe killing blow x300
I went to Cape Terrigan went fairly fast since could do Sand Lizards and Raptors there
Trial 1855: Birds - Catastrophe killing blow x300
Old School level 54 Bird camp, was there for like 5 hours always pops and went fairly fast.
Trial 2265: Beasts - Catastrophe killing blow x400
Ule Range at the beginning of the zone there are Rabbits/Tigers and Buffalo all easy to kill.
Another way to make the trials to go faster is after you are done with your first trial find a person who is willing to help you who has an Apoc, makes trials twice as fast.
Hope this helps you :)