  We theoretically propose that the monolayer $A$Ti$X$ family (KTiSb, KTiBi,
RbTiSb, SrTiSn) are potential candidates for large-gap quantum anomalous Hall
insulators with high Chern number $\mathcal{C}=2$. Both of the topology and
magnetism in these materials are from $3d$-orbitals of Ti. We construct the
tight-binding model with symmetry analysis to reveal the origin of topology.
Remarkably, quite different from the conventional $s$-$d$ band inversion, here
the topological band inversion within $3d$ orbitals is due to the crystal field
and electron hopping, while spin-orbit coupling only trivially gaps out the
Dirac cone at Fermi level. The general physics from the $3d$ orbitals here
applies to a large class of transition metal compounds with the space group
$P4/nmm$ or $P$-$42m$ and their subgroups.
