Java Edition:Exit Portal Removal
Since 15w31a (1.9 Snapshot) regenerating the exit portal by either killing or respawning the ender dragon would delete the blocks around it allowing for things such as half beds, doors and floating plants, rails, torches and such until 17w47a (1.13 snapshot).
An easier method existed since 1.10-pre1 which would reset the exit portal and ender dragon whenever relogging during the initial fight.
This also works for regenerating the end pillars from 15w33c - 15w44a
Edge
Half Beds
By placing a bed on the edge of the resetting area you can create half beds of either side.
Inclined rail
By placing rails inclined against the side of a block that is inside of the area, will leave it without a connection.
Top
Support Blocks
Blocks that require to be placed on something such as plants, pressure plates, redstone repeaters comparators etc. can be left floating when placed on a block inside the resetting area.
Bottom
Doors and Tall Plants
By placing the doors or plants under the lip of the exit portal will replace their upper half with endstone
Any Surface
Blocks that require support such as signs, banners and torches etc. can be left floating by placing them attached to a block inside of the resetting area.





