Among the most commonly available floppy lettuces in the UK are Round, Butterhead, Lollo Rosso, Escarole, Oak Leaf and Little Gem. Crisp include Iceberg, Cos, Curly Endive (also known as Frisée), Web's Wonder and Romaine.
If you may have any food allergies, or underlying health issues these must always be taken into account. If you are a diabetic and not sure how certain foods may affect your blood sugars, test is best, i.e. use your meter.
All the best Jan