This is my idea about 7 season.
I think that new villian should be Nero. He is from book "Qou Vadis" Henryk Sienkiewicz. He was exiled from his realm, Ancient Rome Realm. He was found by Black Fairy. Fiony said him that when she were killed, he had to find the way to circumvent the rules of magic. After Fiona death, Nero burned Storybrooke and during the confusion he kidnapped Henry. Emperor threatened that unless Emma and her family bring the 3 things from other worlds, he'll kill Henry. Emma took up the task. First thing was magic pocket watch. It is the Polynesia's World. There they (Emma and her family: Snow White, Charming, Regina, Zelena, Hook, Rumple and Belle) met Moana, who helped them find this watch. Item was on the shell of the Tamatoa (master of Cyrus, who wanted a lot of trinkents and to can carry it on his back). It was a little problem, but they won. They discovered that watch was broken. They had to go to the inventor of the watch, Traveler from "The Time Machine" H.G.Weels. He lived in the Victorian England. There they met Alice and Cyrus, who had problems with Jafar. Traveler fixed watch. They had one thing. Second thing was on the cemetery in the Victorian England in the tomb of Ebenezer Scrooge. There they found that they have to choose. There is a lampshade, a horn and a sticker. First they chose sticker, but that was the bad idea. New Dark Curse plumed. Curse made that family forget about yourself. They were in the other realms.
1. Hook and Emma were in the Renaissance Verona World. There they weren't in love. Hook met Juliet and Emma met Romeo. They fell in love. Belle was in the Emma's medallion. She was the only one, who remember life before.
2. Snow White and Charming were in World War I World. They were in love, but they can't kiss. Charming was the snowman and Snow White was the gas furnace. She was screwed to the wall and he couldn't go into house, because he can thaw.
3. Zelena and Regina land in the Middle Aged Slavs' World. They were sisters called Alina and Balladyna. They met Kirkor and the Solitary (Rumple). They went to the forest picking raspberries. One, who pick more, wins the heart of Kirkor. Almost Zelena killed Regina, but in the last second they hugged. It broke curse.
Family came back to grave and they get horn, but it teleported them to the Christmas World. There they met Santa Claus, who gave them presents. After that they came back, they got the lampshade.
Third thing was in the Enchanted Forest. It was the pink wand made from the rose. It can make true love. They got it and came back to Storybrooke.
There they didn’t want to give the items to Nero. Emperor was angry. Fight started. Nero got the magic lampshade. He used it. He turned back into live everyone, who died during six seasons. They remember everything.
When villains discovered that they are on a hiding to nothing, they made plan. They made curse. It was the worst curse ever. It made villains happy.
☀ Black Fairy was in the Rumpelstiltskin’s castle with Malcolm, Rumpelstiltskin, Belle, Bealfire and Gideon. Castle is in the Enchanted Forest. Rumple is the most famous knight, who was helping during the Troll War. The war ended years before.
☀ 1920’s England realm changed that Cruella de Vil was queen there, known as the Cruella I the Great. She has everything, Isaac included. Isaac was famous writer. They lived in Buckingham Palace, that is spotted like Dalmatian.
☀ Storybrooke (changed name into Millstown) was ruled by Zelena, Regina, Cora and Valet. Zelena and Regina were very cruel. Regina was the wife of Daniel and Zelena wife of the Robin Hood. Merry Men were the policemen of Millstown.
☀ Hades was the king of Olympus and Zeus was trapped in Underworld.
☀ Ingrid had a magic family with Emma and Elsa. They lived in Ice Age World.
☀ Mr Hyde got married with Mary in Victorian England. Dr. Jekyll was in an insane asylum with Alice and Cyrus. Dr. Lydgate was very rich and he had hair.
☀ Hook and Milah were the marriage of pirates. Their captain was the Blackbeard. Hook had sometimes seasickness after dring rum.
☀ Prince Charming lived in the country with the Snow White. They had 2 kids: Neal and Henry. With them lived parents of Prince Charming.
☀ Jafar was the king of Agrabah. Alladin and Jasmine were in the prison without memories.
☀ Arendelle was ruled by Hans and his brothers. Anna was the wife of Hans. Kristoff was the rock troll. Sven was the statue.
☀ Ruby lived with her mother in the Enchanted Forest. Granny worked in the tavern in the Wild West Realm
☀Dwarfs and Fairies worked in the mines. They were prisoners of the Grumpy and his wife, Nova. Mines are the new world called "World under the World". Here's a lot of coal and suffer, but no diamonds and gems.
☀ Pinocchio was the wooden. Hopper was cricket again. Geppetto showed them in the circus in the Tuscany World. Parents of Hopper were human and they worked in circus.
☀ Sidney Glass was the mirror, again. He worked for Evil Queen.
☀ Nero was the emperor of Rome.
☀ Camelot was ruled by sir Lancelot and Guinevere. Artur was jester.
☀ Wonderland was ruled by Jabberwocky. Anastasia and Will Scarlet were frightened villagers.
☀Cinderella and her prince was put in 1980s World, where Cinderella din't remember prince, and prince was single father who is broken. Cinderella was butterfly from rich house. Her stepfamily was the neighbour of her. She lived in one house with her dad and mother.
☀ Parents of SnowWhite were farmers in Kansas.
☀Sherriff Graham was the detective in '60's America World. 'He was black-and-white. He interacted with Sherlock Holmes.
☀Maid Marrian and her son, Roland were citizens of Mllstown. She didn't remeber who is a father of the child.
☀Prince James and Jack were marriage. King George was polite.
☀Lizard is a real lizard.
☀Helga and gerda lived in Millstown, working in ice cream shop.
Then Henry crossed the world looking for adventure. He found Emma. They hugged. He kissed her and the curse was broken. All death persons died again. Nero was killed by angry mob.