Here is a list of all enums with links to the classes they belong to:

Bit : circt::FVInt
BuildMode : circt::firtool::FirtoolOptions
CasePatternKind : circt::sv::CasePattern
CombLogic : circt::calyx::PredicateInfo
Direction : circt::hw::ModulePort, circt::msft::PlacementDB, esi::BundleType
InfoLocHandling : circt::firrtl::FIRParserOptions
Kind : circt::firrtl::FIRToken, circt::firrtl::InstanceInfo::LatticeValue, circt::om::evaluator::EvaluatorValue, circt::pretty::Token
Level : esi::Logger
LocationInfoStyle : circt::LoweringOptions
ManifestMethod : esi::backends::cosim::CosimAccelerator
Mode : circt::ImportVerilogOptions, esi::backends::trace::TraceAccelerator, esi::ReadChannelPort
OutputFormat : circt::rtg::RtgToolOptions
Port : circt::calyx::PredicateInfo::InputPorts
PrintBreaks : circt::pretty::PrettyPrinter
RandomKind : circt::firtool::FirtoolOptions
RefTypeUsage : circt::firrtl::WiringProblem
Strategy : circt::pipelinetocalyx::LoopScheduleToCalyxPass::LoweringPattern
Type : circt::arc::StateInfo
WireSpillingHeuristic : circt::LoweringOptions