You've probably heard about SFDX, for developers, automation, continuous integration, testing, scratch orgs, etc.

It's also, incidentally, a fantastic login manager.

Setup

  1. open a terminal
  2. type sfdx force:auth:web:login -a SomeAlias

this takes you to a login, and after that, the org is stored in your sfdx's list.

Use

Cool. Now, anytime I need to open that org, I can just say
sfdx force:org:open -u SomeAlias

If you can't keep up with all the aliases, you can always
sfdx force:org:list to get a list of them.

Specific Locations

But wait, I need to get somewhere in that org really quickly.

You can add something like
sfdx force:org:open -u SomeAlias -p /one/one.app#/sObject/Project__c/list?filterName=00B46000001g7CrEAI

where -p is the path to the page you want to open.

Bash Alias

Of course, that's a lot of typing. Extreme laziness means editing your .bash_profile with something like this
alias platformers="sfdx force:org:open -u platformers -p /one/one.app#/sObject/Project__c/list?filterName=00B46000001g7CrEAI"

Aside: an alias in bash is like a shortcut--when you time the alias word, it reads it as whatever is after the equal sign, and has no relationship to sdfx org aliases.

Now, I can just type platformers in any terminal and, boom, I'm there.

If it still seems like to many keystrokes, you could make the alias something even shorter like p