1) be a relatively new startup;
2) be for the main landing page;
3) not be a personal site (unless you are a consultant);
4) and please pick just one.
With all of the new tld's (and near .com saturation), I'm curious what folks are using nowadays.
What on earth are you talking about? If a name is taken, a name is taken.
The character limit on DNS is 253; so you've got enough space to be imaginative.
Further; if your startup name is already taken, then you probably should make a new name. Someone who just browses the site won't be able to remember if it was a .io, or a .xyz, or .space. They really don't care, and the first thing they'll try is .com, since that was/is the unwritten standard.