1. Follow Hallow's Unity Engine Ripping Tutorial, using AssetStudio. You want to grab the whole hierarchy of a temtem, named "MXXX" (where XXX is the Temtem's Tempedia number)
NOTE: Temtem introduced in Alpha 0.7 onwards may not have the "MXXX" hierarchies. Grab the ones with "MXXX_InBattle" instead, then go into AssetStudio's options menu and under FBX export options, untick animations. If you don't, the model won't be in T-Pose. Also the InGame ones are using LODs and may be a lower quality?
2. Open the fbx labelled "MXXX" in Noesis. This is a T-Posed, rigged model with no animations, unlike the fbx files in the other folders, which are animated.
NOTE: If you're ripping a Temtem introduced in Alpha 0.7 onwards, this model may be labelled "MXXX_InBattle" instead
3. Export the model as .dae and check the option to flip the UVs. Put it in a new folder, named appropriately.
4. Grab the regular texture from "MXXX_InBattle" and copy it into your new folder. If it's got large amounts of transparency where there shouldn't be, change the settings in AssetStudio to export the texture as .bmp, it'll fix it. Resave the exported texture as a .png and all should be well. There may also be "mask" textures. Grab those too, they're usually for emissives or other effects.
5. Use AssetStudio to find and export the Texture2D "MXXX_Dif_Luma" and copy that into your new folder. This is the luma texture.
6. Import the .dae into the model editor of your choice and apply the textures, ensuring the rig is there and looks correct
7. Export a new .dae so the textures stick, and name it the Temtem's name for ease of use. Do not overwrite the original .dae exported by Noesis, as re-exporting over old .dae files seems to turn the armature upside-down
8. Check the new .dae one last time to ensure everything exported correctly.
9. Delete everything in the folder so that only the final .dae file, the texture, effect masks (if applicable) and the luma texture remain
10. Zip it up, it's ready to submit! For the sake of uniformity, a ripped Temtem model should be placed under the section "Temtem" and named "#XXX Name", for example "#001 Oree"

(Koish heavily uses detail masks and custom colour textures and has mesh variant stuff that I have no clue how to get to work correctly. If someone wants to help, please do. I can provide the meshes and textures. Need to work out how to read material files to get the right colours but it'll be a pain in the ass.)
-Koish (Water)
-Koish (Fire)
-Koish (Nature)
-Koish (Neutral)
-Koish (Toxic)
-Koish (Crystal)
-Koish (Mental)
-Koish (Melee)
-Koish (Electric)
-Koish (Wind)
-Koish (Digital)
-Koish (Earth)

(Chromeon has weird colour masking stuff like Koish. Need to work out how to read material files to get the right colours but it'll be a pain in the ass.)
-M004 Chromeon (Digital)
-Chromeon (Fire)
-Chromeon (Nature)
-Chromeon (Neutral)
-Chromeon (Toxic)
-Chromeon (Crystal)
-Chromeon (Mental)
-Chromeon (Melee)
-Chromeon (Electric)
-Chromeon (Wind)
-Chromeon (Water)
-Chromeon (Earth)

(These two seem to have issues with their bones on export, like they're not weighted or parented properly. No clue how to fix. Can provide models if asked.)
-M046 0b1
-M047 0b10

-Dr Sasaya (Can't seem to get the goggle texture to look right)