That's a tiny block.
IPv6 addresses aren't counted individually, except by cheapskate VPS hosting companies. More often, a /64 subnet containing 2^(128-64) addresses – 18 billion billion addresses – is used as a single unit of distribution. If your ISP claims to support IPv6, expect that you'll get at least one /64.
Many ISPs freely provide their customers with a larger prefix, e.g. /60 or /56; this isn't said to have 2^(128-56) addresses, but rather "16 subnets" or "256 subnets". Each subnet has a practically infinite number of addresses – it's the number of subnets that is limited.
In both cases, residential ISPs typically use DHCPv6-PD to allocate prefixes on demand, so that's something your router needs to do automatically. Some ISPs might instead do static assignments via support tickets.
(Routing tables can work with any prefix, from /0 to /128, but certain auto-configuration protocols expect /64 for the on-link subnet. You can use e.g. /96's or /112's but it'll be troublesome and not worth the time. Hence the usage of /64 as a standard unit.
That said, of course, if you're doing a special-purpose scheme like the christmas-tree thing, you're completely free to ignore subnetting and use all available bits as you wish.)
As you can see, even a single standard subnet has a decent amount of addresses to work with. A /64 means it uses 64 bits for the 'network' part, so you have 128-64=64 bits available for yourself: that's already enough to encode RGB color, position, and intensity. Having a /56 would give you 128-56=72 bits, and so on. (For comparison, your original request of 1000 addresses is approximately a /118 with only 10 host bits.)
But if you want more than that, a /48 is normal starting prefix size for business customers (up to /44, or at least so the recommendation goes). Additionally, both of the largest surviving "IPv6 tunnel broker" companies – NetAssist and Hurricane Electric – provide a free /48 to anyone who signs up on their website. In both cases, this means 65536 subnets or 80 freely usable bits.
Finally, let's say you're an ISP, then becoming a direct member of a RIR (regional Internet registry) will give you a /32 up to /29 allocation just to begin with. A /32 contains 4294967296 subnets – as many as there are IPv4 addresses including even the reserved ones – and each subnet still has the same "practically infinite" amount of addresses.
That's a large block.
1A single, standard IPv6 network is
/64
, which is18,446,744,073,709,551,616
host addresses. Most sites will be assigned a/48
prefix (the largest prefix or smallest number of hosts able to be routed on the public Internet) which is65,536
/64
networks. – Ron Maupin – 2019-01-15T05:20:47.253