The ATNF Pulsar Catalog: A general catalog includes all published rotation-powered pulsars, as well as anomalous X-ray pulsars (AXPs) and soft gamma-ray repeaters (SGRs) with detected coherent pulsations.
Pulsars in Globular Clusters: An up-to-date catalog includes all the pulsars discovered in the Galactic globular clusters.
Catalog of Parameters for Milky Way Globular Clusters: A catalog contains basic parameters on distances, velocities, metallicities, luminosities, colors, and dynamical parameters for 157 objects classified as globular clusters in the Milky Way galaxy.
Fundamental Parameters of Galactic Globular Clusters: Information on the fundamental parameters of 168 Galactic globular clusters derived by fitting N-body models to an up-to-date compilation of ground-based radial velocities, Gaia DR3 proper motions and HST based stellar mass functions.
Data Archives
Chandra Data Archive: Access data observed by Chandra X-ray Observatory. In particular, ChaSeR is a very useful search and retrieval interface to access Chandra data.
XMM-Newton Science Archive: Access to data from the XMM-Newton mission including searches on the associated EPIC and OM catalogues.
The Mikulski Archive for Space Telescopes (MAST): An astronomical data archive focused on the optical, ultraviolet, and near-infrared. MAST hosts data from over a dozen missions like Webb, Hubble, etc. E.g. HST UV Globular Cluster Survey ("HUGS"), a database contains catalogs and astrometrised stacked images of 56 globular clusters and one open cluster.
The Strasbourg astronomical Data Center (CDS): A database of the collection and worldwide distribution of astronomical data and related information. The CDS data can be accessed using e.g. VizieR service.
Tools
Chandra Interactive Analysis of Observations (CIAO): The software package developed by the Chandra X-Ray Center for analysing data from the Chandra X-ray Telescope. Sherpa: CIAO's modeling and fitting package. ds9: An image display and visualization tool for astronomical data.
BXA (Bayesian X-ray Analysis): Connecting the X-ray spectral analysis environments Xspec/Sherpa to the nested sampling algorithm UltraNest for Bayesian Parameter Estimation and Model comparison.
Chandra Proposal Planning Toolkit: Including useful tools like conversion of fluxes and count rates, conversion of calendar and time, etc.
photutils: a Python package for detecting and performing photometry of astronomical sources.
TOPCAT: an interactive graphical viewer and editor for tabular data.