tmls is a CLI overlay for tmux ls that facilitates selection and attachment of sessions. Navigate active sessions with ↓/↑ or j/k, select one via enter, or exit with ctrl+c or q. You can create a new session in the current working directory by hitting Tab and entering a session name, and switch back to session selection by hitting Tab again.
You may build tmls on your own (see below) or simply install via go get github.com/jankaszel/tmls. Alternatively, you may obtain pre-built binaries on GitHub for macOS or Linux.
You'll need Go (I recommend using a version newer than 1.13). Obtain the source via Git or go get -d github.com/jankaszel/tmls, navigate to the cloned directory and build with go build. You may run go install, which will make the binary globally available to your system.
tmls is licensed under GPL.