If this is your first one: start with a unicorn horn or a smooth tentacle. Spiral ridges and gentle suckers give you the fantasy shape without the texture being the whole event. Deep knots, hard bulbs and pronounced scales are where people find their limit, and it is easier to work up than to return something.
If you already own realistic toys and want something different: go for the texture, not the size. The reason to buy a fantasy shape is the ridges and suckers, and you get all of that in a modest girth. Picking the biggest one in the range is the most common way to end up with a toy that sits in a drawer.
If you are buying for pegging or harness use: check for a flared base, not just a suction cup. Many fantasy shapes have a broad decorative base that happens to work in a harness, and some do not. The product page will say if it is harness compatible.
On materials: silicone is soft, detailed and body temperature. Glass is rigid, smooth and takes temperature. Silicone needs water-based lubricant, because silicone lubricant degrades it. Glass takes any lubricant. Both are non-porous and body safe, and both wash with warm water and mild soap.
On size, one more time: read the diameter, not the length. A 7 inch tentacle with a 2 inch bulb is a bigger ask than an 8 inch smooth shaft. Measure something you already like and use that number.
The honest downside: these are divisive, and a photo will not tell you which way you will land. The same ridge that one person calls the best sensation they have had is too much for the next person. Reactions split, so buy the moderate version of a shape you are curious about before you commit to the extreme one.
