Wikipedia actually has historical maps of FBS teams.
https://en.wikipedia.org/wiki/NCAA_Divis...ubdivision
"...In order to retain FBS membership, schools must meet several requirements.[13] FBS schools must have an average home attendance of at least 15,000 (over a rolling two-year period).[13] An FBS school must sponsor a minimum of 16 varsity intercollegiate teams (including football), with at least six men's or coeducational teams and at least eight all-female teams.[13] Across all sports, each FBS school must offer at least 200 athletic scholarships (or spend at least $4 million on athletic scholarships) per year, and FBS football teams must provide at least 90% of the maximum number of football scholarships (which is currently 85)....[13]"
Division I without FBS only requires 14 sports and several million less in financial aid.
"...Financial aid representing a minimum aggregate expenditure of $1,555,808 in 2017-18 (with at least $777,904 in women's sports) and $1,604,038 in 2018-19 (with at least $802,019 in women's sports) exclusive of grants in football and men's and women's basketball, provided the aggregate grant value is not less than the equivalent of 38 full grants, with at least 19 full grants for women. The Strategic Vision and Planning Committee shall adjust the minimum aggregate figure annually to reflect inflation, based on changes in average national tuition charges for regionally accredited institutions. The committee shall announce the revised figure in the fall each year for the following academic year. If the institution does not sponsor men's or women's basketball, the minimum aggregate expenditure must be $1,027,152 in 2017-18 and $1,058,994 in 2018-19 for the gender without the basketball program, but in no case fewer than the equivalent of 29 full grants for that gender;
© A minimum of the equivalent of 50 full grants (at least 25 full grants in women's sports), exclusive of grants awarded in football and men's and women's basketball. If the member institution does not provide men's or women's basketball, it shall sponsor a minimum of 35 full grants in the sports program for the gender without the basketball program; or..."
https://web3.ncaa.org/lsdbi/search/bylawView?id=32876