Fizzbuzz in any base
JavaScript (ES6),  117  116 bytes
Outputs comma-delimited digits, each digit being expressed as a decimal quantity (e.g. \$19_{20}\$ is \$19\$ and \$21_{20}\$ is \$1,1\$).
b=&gt;(g=n=&gt;n&gt;1?g(n-1)+`
`+((s=n%(b+2&gt;&gt;1)?'':'Fizz',n%(b/3+3.9|0)?s:s+'Buzz')||(g=n=&gt;n?[...g(n/b|0),n%b]:s)(n)):1)(5e3)

Try it online!
(limited to 100 so that TIO's output does not blow up)