Rare begonias are highly sought after by collectors and enthusiasts due to their unique foliage, vibrant colors, and limited availability. Some notable rare begonias include Begonia rex, known for its striking patterned leaves; Begonia pavonina, prized for its iridescent foliage; and Begonia coccinea, appreciated for its bright red flowers. These plants often thrive in specific conditions, requiring careful attention to humidity, light, and watering to ensure their health and vibrant appearance.