| Index | Ligand Name | Structure | PDB code | Compound Potency nM |
| 1 | kee | Design, synthesis, and biological evaluation of potent and selective Class IIa HDAC inhibitors as a potential therapy for Huntington's disease | 4cby | 20 |
| 2 | otf | Potent, selective and CNS-penetrant tetrasubstituted cyclopropane class IIa histone deacetylase (HDAC) inhibitors | 5a2s | 20 |
| 3 | tfg | Structure of HDAC4 catalytic domain bound to a trifluoromethylketone inhbitor | 2vqj | 367 |
| 4 | ha3 | Structure of HDAC4 catalytic domain bound to a hydroxamic acid inhbitor | 2vqm | 978 |