Afaik there are
function BsfByte(Const AValue: Byte): Byte;[internproc:fpc_in_bsf_x];
function BsrByte(Const AValue: Byte): Byte;[internproc:fpc_in_bsr_x];
function BsfWord(Const AValue: Word): cardinal;[internproc:fpc_in_bsf_x];
function BsrWord(Const AValue: Word): cardinal;[internproc:fpc_in_bsr_x];
and also dword, qword in trunk versions which are afaik somewhat like clz/ctz, though the error on no bit is different. See attached help page. ffs might be clz on not value.
But in general intrinsics are only added when they are actually used.