Low-tech starter list
Java fern, Anubias nana, Cryptocoryne wendtii, Amazon sword, Vallisneria. All tolerate lower light and no CO₂.
Medium-tech additions
Ludwigia repens, Rotala rotundifolia, dwarf sagittaria, pearl weed. These want better light but tolerate low CO₂.
High-tech only
Carpeting plants (Monte Carlo, HC Cuba, dwarf hairgrass), most reds, Buce. These need CO₂ to thrive.