You can personalise each of your tags when you buy them by adding up to four characters, one large emoji, or a combination of both, but there are, as yet, no alternative colour options. It’s white and silver or nothing.
Each AirTag is powered by a single, user-replaceable CR2032 battery that lasts up to a year and they’re dust- and water-resistant as well, with an IP67 rating that means they’ll survive a dunking in water up to 1m deep for up to 30 minutes.
As for accessories, Apple produces its own range of these, but they’re expensive so you might want to look elsewhere for these. The leather key rings are nice but they cost £35 each, and the baggage loops in silicone rubber or leather, are also pricey at £29 and £39, respectively.