1. Lighting, lighting, lighting! Overhead recessed LED placed about 2.5’ to 3’ apart.
2. Full bathroom, and also a small kitchenette (apartment sized fridge with ice, minimal cabinetry for snacks, microwave)
3. Large central island (6’ by 8’?) with cutting area on one end, pressing in the middle, and recessed sewing machine on the other end. Storage underneath, including plenty of drawers for notions and hanging area for rulers and templates.
4. Fabric cabinetry (think IKEA Billy cabinets) with glass fronts down one long wall.
5. Longarm down the opposite long wall.
6. Siting area with sofa or recliner or futon, TV, small desk with computer.
I think this covers the majors.