Simple Spikes adds, as the name suggests, a set of simple spikes to improve and simplify mob farms. Using these spikes will serve the same purpose as a huge drop to deal fall damage, except you don't need to go through the effort of creating a 20-something block deep hole, saving time.
Simple Spikes currently adds 8 types of spikes, all having varying features and damage.
Wooden Spikes - Deals 1 damage, but is easy to get.
Stone Spikes - Deals 2 damage, a small upgrade from Wooden Spikes.
Copper Spikes - Great if you need large amount of spikes, deals 3 damage.
Iron Spikes - The 'default' spikes. Deals 3 damage.
Gold Spikes - Also deals 3 damage, but doesn't kill the entity, leaving it with half a heart.
Diamond Spikes - Deals 6 damage and also leaves the entity with half a heart.
Netherite Spikes - Deals 10 damage, leaves the entity with half a heart, and pierces through armor.
Slime Spikes - Deals 3 damage, and entities bounce on the spikes.