One Piece is an ongoing anime series that started in 1999. As of now, 1122 episodes of One Piece have been aired. With a total of 94 reported filler episodes, One Piece has a very low filler percentage of 8%.
Manga Canon Episodes
1-44, 48-49, 52-53, 62-67, 70-92, 94-97, 100, 103-130, 144-195, 207-212, 217-219, 227-278, 284-290, 293-302, 304-316, 320-325, 337-353, 355-381, 385-405, 408-417, 422-425, 430-452, 459-488, 490-491, 493-496, 500-505, 507-519, 521-541, 543-573, 579-589, 591-624, 629-632, 634-652, 654-656, 658-678, 680-689, 691-730, 732-736, 739-746, 752-774, 776, 779, 783-788, 790-802, 804-806, 808-877, 880, 886, 891-894, 897-906, 908-923, 925-987, 990, 992-1028, 1031-1083, 1085-1122
Mixed Canon/Filler Episodes
45-47, 61, 67-81, 101, 226, 354, 421, 489, 520, 574, 625, 628, 633, 653, 657, 679, 690, 731, 738, 751,777-778, 789, 803, 807, 878-879, 881-885, 887-890, 924, 988-989, 991
Filler Episodes
54-60, 98-99, 102, 131-143, 196-206, 220-225, 279-283, 291-292, 303, 317-319, 326-336, 382-384, 406-407, 426-429, 457-458, 492, 542, 575-578, 590, 626-627, 747-750, 780-782, 895-896, 907, 1029-1030
Anime Canon Episodes
50-51, 93, 213-216, 418-420, 453-456, 497-499, 506, 737, 775, 1084