Minato probably does not know any-other techs. Reasons why?
Kakashi was renown for his skill in over 1000 jutsu, but we have seen less than 50 or so. People knew about the other jutsu though.
Hiruzen was renown for his mastery in every jutsu native to Konoha. We seen his use like 10-20 jutsu. People knew about the other jutsu though.
Tobirama, (less panel time than Minato), was said to have skill in S/T Jutsu, edo tensei, and mastery in Suiton techniques. We have seen him use like 3-5 techniques. People knew about his other jutsu though.
In conclusion, even if Minato had other jutsu, people would have known about it. He might have some seals, but no super-cool ninjutsu skills.