Just recently found out other workshop manuals: https://charm.li - https://charm.li/about.html
It has many more brands than the Celica, however the manuals only will go until 2013.
There are manuals the Celica Gen7
https://charm.li/Toyota/2003/Celica GT-S L4-1.8L (2ZZ-GE)/Repair and Diagnosis/
https://charm.li/Toyota/2003/Celica GT L4-1.8L (1ZZ-FE)/Repair and Diagnosis/.
Celica Gen 6:
https://charm.li/Toyota/1998/Celica ST Liftback L4-2164cc 2.2L DOHC (5S-FE) MFI/Repair and Diagnosis/
https://charm.li/Toyota/1998/Celica GT Liftback L4-2164cc 2.2L DOHC MFI/Repair and Diagnosis/
GT86:
https://charm.li/Scion/2013/FR-S F4-2.0L (FA20)/Repair and Diagnosis/
I am also not entirely sure exactly what is the original source of the manuals, does anyone know?
It is possible to download the Torrent (700GB) and extract the Celica parts, but I don't know yet how easy would be the extraction. If they are something we don't have yet, does it worth to have an "offline" version of this just in case the website goes down?