If gamers have now not gotten them in previous years from lidakun's blog

If gamers have now not gotten them in Animal Crossing Items  previous years, there are new fish and bugs to trap that show up in June. Players can donate them to the museum and get toward completing their Animal Crossing: New Horizons museum collection. Or they can maintain them and display them or gift them to other citizens. Alternately, they can promote them for Bells.

June is not the busiest month for  Buy Animal Crossing Items events in Animal Crossing: New Horizons, however some do run for more than one days. Of path, this is applicable to Nook buying days too, so there is lots of time to finish the event or buy the unique occasion gadgets.