I think a lot of people have said this.
Plantera: Destroying blubs won't summon plantera but dropping the summoning item.
Lunatic cultist: Drop by enemies in dungeon. Sometimes the entry is destroyed so make the summoning item available before defeating it.
Rain: Dropped by enemies in rain or made with something in ocean.
Windy day: Dropped by enemies in windy day.
Sandstorm: Make it as a part of windy day, just like blizzard as a part of rain.
Slime rain: Made by gel or dropped by slimes.
Martian madness: Dropped by Martian probe when it is killed or made with Martian conduit plating.
Change some ways to get some summoning items:
Skeletron and wall of flesh: Change the doll to another thing to summon it directly. Make it available without guide and clothier.
Frost legion: Make snow globe dropped by snow enemies. Because presents can only be available in Christmas. Or make it as a part of frost moon.
Plantera: Destroying blubs won't summon plantera but dropping the summoning item.
Lunatic cultist: Drop by enemies in dungeon. Sometimes the entry is destroyed so make the summoning item available before defeating it.
Rain: Dropped by enemies in rain or made with something in ocean.
Windy day: Dropped by enemies in windy day.
Sandstorm: Make it as a part of windy day, just like blizzard as a part of rain.
Slime rain: Made by gel or dropped by slimes.
Martian madness: Dropped by Martian probe when it is killed or made with Martian conduit plating.
Change some ways to get some summoning items:
Skeletron and wall of flesh: Change the doll to another thing to summon it directly. Make it available without guide and clothier.
Frost legion: Make snow globe dropped by snow enemies. Because presents can only be available in Christmas. Or make it as a part of frost moon.