For these other companies what rockets are good for level 1 cert? Only one site so far had a listening of rockets listed for level 1 cert.
If you are going for your L1, you should be able to answer this yourself!
"Know what the numbers mean"
L1 requires you launch an H or I motor. Some are 29mm, some are 38mm. From this, we know what motors are available, and we know we want something that isn't a "kick".. Let's aim for an H128 (or there abouts..) SO, we know anything over 10 or 15lbs is going to be too much. 3-5lbs is ideal. There are more 'H' motors in 29mm than 38, so it's likely better to look at 29mm. (You can use a 38mm and use an adapter to 'go down' to 29mm..)
We also know most "HPR" rockets typically start at about 3" in diameter, and go up from there.. and we know we the larger the diameter, the greater the frontal area, therefore more drag.. and a 4" tube is pretty common..
SO, having said the 2 above: Any 3" dia or greater, 3lbs, 29mm Mount will suit an L1 attempt. There are some other factors that can help you decide, but these are personal choices.. fin shape, design, complexity, materials, etc..
But let's judge a few "suggestions":
LOC Weasle:
skinning body & light, so it'll go high!
Lock 7" Goblin
Too heavy
Loc 4" Goblin:
4" dia, light, and has an adjustable motor system, of which one is a 29mm. This is likely a good choice.. But it has no payload bay. Needed?
A lot of these (especially Madcow) have Rocksim / Open Rocket files, so you can download teh file, and 'sim it' with the intended motors and see what kind of flight you can expect.
You could also use the Estes Leviathan on an H97..
FYI: I did my L1 on a Wildman Darkstar Jr.