Here’s my collection of propagation and mapping links curated from the web.

HF Propagation

KC2G HF MUF and others  Ionospheric propagation maps (MUF and critical frequency) by KC2G.

VOACAP HF Prediction.  Predict your HF path and frequency.

NVIS MUF (foF2) and others from Australian Space Weather Services

VHF Propagation

Based on realtime APRS reports.  Zoom in on an area of interest and click about.

Mapping

Worldwide Grid square locator. Quick and easy to use.