Russian with User:Yair rand/newentrywiz.js
I don't quite understand the usage of numbers here but m stands for masculine, f for feminine, n for neuter, an for animate, in for inanimate, p for plural (with nothing else). They can be used in any combination (like with other languages). p may appear on its own when gender or animacy is not known or not important. There can be nouns with more than one gender in the header.
Verbs can be impf - "imperfective", pf - "perfective", the other equivalent is usually provided, e.g. скрести. These two parameters and all genders are valid to all Slavic languages, although animacy may not be important for some genders in some Slavic languages, it is used for consistency and doesn't cause errors in Slavic languages. @CodeCat may give you some hints on gender handling modules. So, if you make it for Russian it can be copy-pasted for all Slavic languages but Serbo-Croatian uses different formats for imperfective/perfective.
Now, an important question, how do I enable it (apart from having it in User:Atitarev/common.js and hard-refreshing) and use this tool. Say, I want to create аадсфсдфзфздффгд?