An accessory (700, 900, 1000, 1100, 1200, 1300, 1400, 1500) for coupling to an attachment mechanism of an oscillating power tool, the accessory comprising: a working end portion (702, 902, 1002, 1102, 1202, 1302, 1402, 1502) defining and extending along a working axis (W, W2, W3, W4, W5, W6, W7, W8) and configured to perform an operation on a workpiece; and an attachment portion (704, 904, 1004, 1104, 1204, 1304, 1404, 1504) coupled to the working end portion, the attachment portion including: (a) a top wall (706, 906, 1006, 1106, 1206, 1306, 1406, 1506); (b) a bottom wall (708, 908, 1008, 1108, 1208, 1308, 1408, 1508) spaced apart from the top wall; (c) a peripheral wall (710, 910, 1010, 1110, 1210, 1310, 1410, 1510) extending between the top wall and the bottom wall, at least partially around the top wall, to form at least a portion of a polygonal shape; (d) a generally U-shaped opening (720, 920, 1020, 1120, 1220, 1320, 1420, 1520) defined in the top wall, the U-shaped opening extending along an attachment axis (A, A2, A3, A4, A5, A6, A7, A8) at an angle to the working axis, having a central portion at a center of the attachment portion, and open to a gap (727, 1227, 1327, 1427, 1527) in the peripheral wall; and (e) a plurality of radial openings (730, 930, 1030, 1130, 1232a-c, 1234a-f, 1332a-c, 1334a-f, 1432a-i, 1530) defined in the top wall and arranged between the U-shaped opening and the peripheral wall, whereby the peripheral wall, the U-shaped opening, and the plurality of radial openings are configured to couple the attachment portion (704, 904, 1004, 1104, 1204, 1304, 1404, 1504) to at least two different configurations of accessory attachment mechanisms (110, 210) for oscillating power tools. a working end portion (702, 902, 1002, 1102, 1202, 1302, 1402, 1502) defining and extending along a working axis (W, W2, W3, W4, W5, W6, W7, W8) and configured to perform an operation on a workpiece; and an attachment portion (704, 904, 1004, 1104, 1204, 1304, 1404, 1504) coupled to the working end portion, the attachment portion including: (a) a top wall (706, 906, 1006, 1106, 1206, 1306, 1406, 1506); (b) a bottom wall (708, 908, 1008, 1108, 1208, 1308, 1408, 1508) spaced apart from the top wall; (c) a peripheral wall (710, 910, 1010, 1110, 1210, 1310, 1410, 1510) extending between the top wall and the bottom wall, at least partially around the top wall, to form at least a portion of a polygonal shape; (d) a generally U-shaped opening (720, 920, 1020, 1120, 1220, 1320, 1420, 1520) defined in the top wall, the U-shaped opening extending along an attachment axis (A, A2, A3, A4, A5, A6, A7, A8) at an angle to the working axis, having a central portion at a center of the attachment portion, and open to a gap (727, 1227, 1327, 1427, 1527) in the peripheral wall; and (e) a plurality of radial openings (730, 930, 1030, 1130, 1232a-c, 1234a-f, 1332a-c, 1334a-f, 1432a-i, 1530) defined in the top wall and arranged between the U-shaped opening and the peripheral wall, whereby the peripheral wall, the U-shaped opening, and the plurality of radial openings are configured to couple the attachment portion (704, 904, 1004, 1104, 1204, 1304, 1404, 1504) to at least two different configurations of accessory attachment mechanisms (110, 210) for oscillating power tools.