Minecraft wiki entry for Hopper_clocks, associated text: 1 Single-item hopper clocks
1.1 Hopper-Loop Clock
1.2 N-Hopper-Loop Clock
1.3 Cooldown Hopper Clock
2 Multi-item hopper clocks
2.1 Ethonian Hopper Clock (EHC)
2.1.1 EHC Variations
2.1.2 Hopper timer
2.1.3 Quick reset EHC
2.2 RS NOR Latch Hopper Clock
2.2.1 1-Wide RS NOR Latch Hopper Clock
2.3 Hopper-Latch Hopper Clock
2.4 SethBling's Hopper Clock
3 Multiplicative hopper clocks
3.1 Multiplicative Hopper Clock (MHC)
3.2 Multiplicative Hopper-Dropper Clock (MHDC)
3.3 Multiplicative Hopper-Latch Clock (MHLC)