Please see the other replies I made. I'm aware of all those plugins, but I'm concerned about the official support they (don't) receive.
I've been using Meteor since early 2013 on all my web projects, and for me the core team goes to the correct feature depth — there's 4000+ packages on Atomosphere — it'd be really hard to determine how deep they should go pulling things into the core.
I guess you want every package to start with "mrt:"?
If something has been brought into the main package, its usually a sign of maturity, and stability and usefulness to a large number of people.