१ Dictionaries
kosha.sanskrit.today
Simultaneously search 30+ dictionaries
spokensanskrit.org
Detailed expert search
sanskrit-lexicon.uni-koeln.de
For offline dictionary apps
Most sites have BOTH vibhakti/declensions & Lakaras
UoHyd संसाधनी
sanskrit.uohyd.ac.in/scl
JNU Samskritam
sanskrit.jnu.ac.in/subanta/genera…
TDIL
tdil-dc.in/san/skt_gen/ge…
Ashtadhyayi.com
bhagavadgita.org.in/declension
Many sites like UoHyd, JNU, TDIL have Sandhi tools (joiner/splitter) attached
For offline use, Vyoma Sandhi app