There. I said it.
As the first of its kind, Bitcoin is beautiful, but so many blockchains have been created since 2009, it's hard to pick which ones actually matter. I'm not talking about whether these networks actually function or if their tokens are good investments. The real question is whether they need to exist in the first place.
There are a few categories of blockchains worth addressing: scams, PhD papers, throughput maximizers, and revolutions.
First up, scams should be pretty self explanatory. These tokens make big promises and ultimately fall short. They might have been started with good intentions, but most likely not.
PhD papers are blockchains that do something (sometimes two things) surprisingly uniquely. Their white papers are full of mathematical proofs, and their founding teams are PhD candidates, researches, or otherwise highly academic. Mostly they focus on increasing decentralization, privacy, or security. Occasionally, they'll focus on throughput. These blockchains may succeed in their goal, but it usually takes some more business minded people joining the team which often leads the whole thing in a different direction than the founders wanted.
Throughput maximizers may also be PhD papers, but don't have to be. Any time a blockchain focuses on how many transactions per second it can support as its main selling point, you know this is what it is. The core belief here is that crypto technology is fundamentally already good enough for the masses, but it needs to be able to support more transactions.
Revolutions are blockchains that accomplish something new that actually matters for moving the space forward. Bitcoin of course set the stage. Ethereum introduced smart contracts. This massively increased accessibility of building decentralized applications for any developer. You no longer had to create an entirely new network just to launch an app.
You can make arguments for other chains being revolutions, but I think you'd only be able to get the majority to agree on those two. Personally, I'm putting koinos in this category because it massively increases access to dApps for normal users who don't buy tokens on the network.
P.S. do you think I missed any categories? Or do you have an argument for an additional project to be considered a revolution? Let me know!