Links I find useful:

CDS's Portal.

Code for finding what constellation your object is in. Original code by Nancy Roman (1987), updated for J2000 coordinates

Annotation in R with expression.

R color palette

Link to Gaia DR2 form on VizieR.

The arXiv sanity preserver.

Object visibility STARALT.

IRTF spectral library

JPL molecular spectroscopic database

Flexible curve fitting tool

PhotoDissociation Region Toolbox