Clear[$globalProperties]; $globalProperties = {OwnValues, DownValues, SubValues, UpValues, NValues, FormatValues, Options, DefaultValues, Attributes, Messages}; ClearAll[getDefinitions]; SetAttributes[getDefinitions, HoldAllComplete]; getDefinitions[s_Symbol] := Flatten@Through[ Map[Function[propMap[ Function[ prop, (* Unevaluated needed here just for Options, which is not holding *) Function[sym, prop[sym]prop[Unevaluated @ sym], HoldAll]]HoldAll] ], $globalProperties ][Unevaluated[s]] ]; ClearAll[symbolMemoryUsage]; symbolMemoryUsage[sname_String] := ToExpression[sname, InputForm, Function[s, ByteCount[getDefinitions[s]], HoldAllComplete] ]; ClearAll[heavySymbols]; heavySymbols[context_, sizeLim_: 10^6] := Pick[#, UnitStep[# - sizeLim] &@Map[symbolMemoryUsage, #], 1] &@ Names[context <> "*"];