Here's another weird one - a Peltier sextuple ingot Rainbo. It's 1 1/8" and near perfectly round without that little nub you can see in pic 2. I gave it to Bill years ago - he really likes the weird stuff too.
Not all Alleys are super busy or even busy at all, I am looking mostly at the color and some pattern traits - the way the orange goes pinkish in some spots, e.g.
At first, I was going to post a pic of myself, but then I realized Art wanted to see weird marbles.
I think this Chalky Vitro Conqueror is pretty weird
Like Art said, it's a Contract Run JABO - not sure which run though. I think most of those marbles were 3/4" like yours, but there were some 5/8" - mostly tank washes, I think.
Learning before spending is definitely the wise thing to do. Typical Conquerors are likely the most common vintage Vitro marble - they mad oodles of them. I like the ones that get wild with the shape of the patch and the distribution of the white color - they can get really cool looking.