Most solution formation processes are net exothermic. A few that are endothermic are:
Ammonium Nitrate (used in cold-packs) in water.
Ammonium Chloride in water.
Potassium Chloride in water.
Sodium bicarbonate in Citric acid/water solvent.
Look up the table of Heat of Formation and Solution in the Handbook of Chemistry and Physics (Chemical Rubber Publishing Co.). In my 43rd edition this table is on pages 1807-1831. The Heats of Solution for numerous inorganic compounds are listed.
Good reference! Mine is 89th Edition, Section 5-85,86, page 864. Be careful to read the definitions to make sure you are selecting the correct values (+/-) heat gain/loss.