K&N Crank case breathers are a popular mod and certainly brighten up the engine bay.
Works Engineering 100% Genuine Universal Mini Engine Breather Air
Universal 25mm Car Motor Cold Air Intake Filter Kit Vent Crankcase
Universal Oil Catch Can Tank Reservoir 2 Port with Removable Valve
SAI FILTER FOR VW / AUDI - ARM Motorsports
3/8 INCH (10MM) Air Breather Filter Universal Crankcase BLUE For
Hose - Breather Filter to Inlet Duct
Car Air Filter Car Racing Sport Air Filter Breather Filter - Temu
Air Filter Breather - 12mm Inlet - Red
BMC Universal Engine Breather Filter 20mm Inlet / 40mm Filter