Here are the data structures with brief descriptions:

CZydisAccessedFlags_
CZydisDecodedInstruction_	Information about a decoded instruction
CZydisDecodedInstructionAvx_	Extended info for AVX instructions
CZydisDecodedInstructionAvxMask_	Info about the embedded writemask-register (AVX-512 and KNC only)
CZydisDecodedInstructionAvxBroadcast_	Contains info about the AVX broadcast
CZydisDecodedInstructionAvxRounding_	Contains info about the AVX rounding
CZydisDecodedInstructionAvxSwizzle_	Contains info about the AVX register-swizzle (KNC only)
CZydisDecodedInstructionAvxConversion_	Contains info about the AVX data-conversion (KNC only)
CZydisDecodedInstructionMeta_	Instruction meta info
CZydisDecodedInstructionRaw_	Detailed info about different instruction-parts like ModRM, SIB or encoding-prefixes
CZydisDecodedInstructionRawPrefixes_	Detailed info about the legacy prefixes (including REX)
CZydisDecodedInstructionModRm_	Detailed info about the ModRM byte
CZydisDecodedInstructionRawSib_	Detailed info about the SIB byte
CZydisDecodedInstructionRawDisp_	Detailed info about displacement-bytes
CZydisDecodedInstructionRawImm_	Detailed info about immediate-bytes
CZydisDecodedInstructionRawImmValue_	The immediate value
C[union].__unnamed0__
CZydisDecodedInstructionRawEvex	Detailed info about the EVEX prefix
CZydisDecodedInstructionRawMvex_	Detailed info about the MVEX prefix
CZydisDecodedInstructionRawRex_	Detailed info about the REX prefix
CZydisDecodedInstructionRawVex_	Detailed info about the VEX prefix
CZydisDecodedInstructionRawXop_	Detailed info about the XOP prefix
CZydisDecodedOperand_	Defines the ZydisDecodedOperand struct
C[union].__unnamed0__
CZydisDecodedOperandImm_	Extended info for immediate-operands
CZydisDecodedOperandImmValue_	The immediate value
CZydisDecodedOperandMem_	Extended info for memory-operands
CZydisDecodedOperandMemDisp_	Extended info for memory-operands with displacement
CZydisDecodedOperandPtr_	Extended info for pointer-operands
CZydisDecodedOperandReg_	Extended info for register-operands
CZydisDecoder_	Defines the ZydisDecoder struct
CZydisDecoderContext_	The decoder context is used to preserve some internal state between subsequent decode operations for THE SAME instruction
C[struct].vector_unified	Contains some cached REX/XOP/VEX/EVEX/MVEX values to provide uniform access
C[struct].reg_info	Information about encoded operand registers
C[struct].evex	Internal EVEX-specific information
C[struct].mvex	Internal MVEX-specific information
CZydisDecoderTreeNode_	Defines the ZydisDecoderTreeNode struct
CZydisDefinitionAccessedFlags_
CZydisDisassembledInstruction_	All commonly used information about a decoded instruction that Zydis can provide
CZydisEncodableInstruction_	This structure is encoder's internal representation of encodable instruction definition
CZydisEncoderLookupEntry_	Used in encoder's primary lookup table which allows to access a set of instruction definitions for specified mnemonic in constant time
CZydisEncoderOperand_	Describes explicit or implicit instruction operand
CZydisEncoderOperandReg_	Extended info for register-operands
CZydisEncoderOperandMem_	Extended info for memory-operands
CZydisEncoderOperandPtr_	Extended info for pointer-operands
CZydisEncoderOperandImm_	Extended info for immediate-operands
CZydisEncoderRelInfo_	Contains information used by instruction size prediction algorithm inside ZydisEncoderEncodeInstructionAbsolute
CZydisEncoderRequest_	Main structure consumed by the encoder
CZydisEncoderRequestEvexFeatures_	Extended info for EVEX instructions
CZydisEncoderRequestMvexFeatures_	Extended info for MVEX instructions
CZydisFormatter_	Context structure keeping track of internal state of the formatter
C[struct].number_format	The number formats for all numeric bases
CZydisFormatterBuffer_	Defines the ZydisFormatterBuffer struct
CZydisFormatterContext_	Context structure that that is passed to all formatter
CZydisFormatterToken_	Defines the ZydisFormatterToken struct
CZydisInstructionDefinition3DNOW_	Defines the ZydisInstructionDefinition3DNOW struct
CZydisInstructionDefinition_	Defines the ZydisInstructionDefinition struct
CZydisInstructionDefinitionEVEX_	Defines the ZydisInstructionDefinitionEVEX struct
CZydisInstructionDefinitionLEGACY_	Defines the ZydisInstructionDefinitionLEGACY struct
CZydisInstructionDefinitionMVEX_	Defines the ZydisInstructionDefinitionMVEX struct
CZydisInstructionDefinitionVEX_	Defines the ZydisInstructionDefinitionVEX struct
CZydisInstructionDefinitionXOP_	Defines the ZydisInstructionDefinitionXOP struct
CZydisInstructionEncodingInfo_	Defines the ZydisInstructionEncodingInfo struct
C[struct].disp	Displacement info
C[struct].imm	Immediate info
CZydisInstructionSegments_	Defines the ZydisInstructionSegments struct
C[struct].segments
CZydisOperandDefinition_	Defines the ZydisOperandDefinition struct
C[union].op
C[struct].op.reg
C[union].op.reg.reg
C[struct].op.mem
CZydisPredefinedToken_
CZydisRegisterContext_	Defines the ZydisRegisterContext struct
CZydisShortString_	Defines the ZydisShortString struct