If I've understood correctly, I can't do anything before the main database entries are added. And that it'll take a lot of work to add even a single entry. So... priorities.
Pelit, Pelaaja, Pelit vuosikirja, and PC Pelaaja are the ones that probably should be added first. Since those had gaming as the main focus. I'll dig up a list of issue numbers if needed, just lemme know.
Mikrobitti and C-Lehti are about 50% gaming content.
Printti was only about 20% gaming. No reviews, but occasional maps and solutions. Not sure if site-relevant.
Don't know enough about Joyboy (probably 100% gaming), Micropost, Enter, and Kompuutteri Kaikille: the last two are likely gaming-light.
As for the hobbyist / game store 'magazines': Trioposti and Com Club were mostly focused on games, MSX Uutiset was gaming/hardware.
And as I mentioned, Nintendo-lehti, Pelimestari, and PC Gamer (Suomi) are translations of English mags and therefore not high priority for archival. Not sure if those are even worth adding here.