Which UltraClear epoxy should I use for pour paintings and resin art?

Use UltraClear Art & Craft Epoxy. It's the product we recommend for pour paintings, for top coating acrylic pour art on canvas, and for coating liquid-art tiles used as coasters. It pours in 1/8" or 1/4" layers, gives you 30-40 minutes of working time to work pigments and adjust details, and is formulated for UV resistance and clarity over white backgrounds so your colors stay vibrant. Instructions: https://ultraclear.helpscoutdocs.com/article/864-art-craft-epoxy-instructions

If you're choosing based on VOCs or toxicity, all UltraClear epoxies are 100% VOC-free and cure into an inert plastic. Incidental food contact poses no issue, so finished art pieces and coasters aren't a concern.

For a thin (1/16"-1/8"), hard, self-leveling top coat over large art panels, either Art & Craft Epoxy or UltraClear Bar & Table Top Epoxy will work. Bar & Table Top is our strongest, most scratch-resistant epoxy and self-levels to 1/8"; Art & Craft gives you the longer working time. One gallon of Bar & Table Top covers 48 sq. ft. as a seal coat or 16 sq. ft. as a 1/8" flood coat, and you lose about 30% if you pour over the edges. Calculator: https://www.bestbartopepoxy.com/pages/epoxy-calculator

For clear art that will be displayed outdoors in the sun, use Bar & Table Top Epoxy and spray a coat of UV polyurethane over it after it cures. No resin is immune to sun damage over time, but the polyurethane adds protection.

Tutorial videos: https://www.bestbartopepoxy.com/tutorial-videos/