Supplement Fig. S1, Fig. S2, Fig. S3, Fig. S4, Fig. S5, Fig. S6, Fig. S7, Fig. S8, Fig. S9, Fig. S10, Fig. S11

Fig. S1 -- The preparation process of confined nanodisks. Fig. S2 -- Identification of elliptical skyrmions. Fig. S3 -- The evolution of magnetic structures as a function of magnetic field at different temperatures. Fig. S4 -- The role of DMI in the formation and stability of skyrmions and magnetic bubbles. Fig. S5 -- Magnetic phase images for transformation between the CCW skyrmion, CW skyrmion, and the bubbles with different symmetries induced by the in-plane fields along the [11 ̅0], [1 ̅1 ̅0], [110] and [1 ̅10] directions, respectively. Fig. S6 -- The transformation between the CW skyrmion (S1) and the bubbles with different symmetries induced by in-plane field along the [1 ̅10] and [11 ̅0] directions, respectively. Fig. S7 -- Two mechanisms of the transition from CW skyrmion (S1) to a CCW skyrmion (S2) induced by in-plane field along the [110] and [1 ̅1 ̅0] directions, respectively. Fig. S8 -- The transformation between the CCW skyrmion (S2) and the bubbles with different symmetries induced by in-plane field along the [110] and [1 ̅1 ̅0] directions, respectively. Fig. S9 -- Two mechanisms of the transition from CCW skyrmion (S2) to a CW skyrmion (S1) induced by in-plane field along the [1 ̅10] and [11 ̅0] directions, respectively. Fig. S10 -- Simulated changes in magnetic structure induced by an in-plane (Bin-plane) field in a Fe1.96Ni0.84Pd0.2P nanodisk with S4 symmetry. Fig. S11 -- The EDS spectrum of Fe1.96Ni0.84Pd0.2P and atomic fraction.