We have some answers for you. A Yellow Alyssum is bright yellow and is tolerant to in drought like conditions. We also have Creeping Phlox and Creeping Thyme. Creeping Phlox comes in a variety of color and is relatively easy to remove if needed, in dry conditions they do need to be watered. Creeping Thyme is a fragrant plant that works as a great filler between stepping stones and things alike.
Rock Cotoneaster is colorful red berries for large areas with lots of room for it to spread out. Last but not least there are Hostas. Hostas are great for adding a variety of things and are very easy to maintain. Be careful though because the deer love them