DDA (digital differential analyzer)
Draws a line by stepping along one axis and adding the slope to the other — simple, but with floating point.
DDA is the naive cousin of Bresenham: compute the slope as a float and add it at each step, rounding to the nearest pixel. Easier to grasp, but the rounding and the floating point made it slower on older hardware — which is exactly why Bresenham existed.
The name comes from analog differential analyzers. In games the famous variant is grid DDA (Amanatides & Woo, 1987): a ray is stepped cell by cell through a tilemap, and it is the engine behind raycasters like Wolfenstein 3D.