How to take top 10 built-in function

Here are at least two ways:

WolframLanguageData[All,
                    EntityProperty["WolframLanguageSymbol", "Frequencies",
                                   {"Corpus" -> "StackExchange"}],
                    "EntityAssociation"] // TakeLargest[10] // KeyMap[CommonName]

or

prop = EntityProperty["WolframLanguageSymbol", "Frequencies",
                      {"Corpus" -> "StackExchange"}];
tmp = EntityClass["WolframLanguageSymbol", prop -> TakeLargest[10]]];
EntityValue[tmp, prop, "EntityAssociation"] // KeyMap[CommonName]

Both give the result

<|"List" -> 0.171144, "Times" -> 0.115336, "Set" -> 0.0546105, 
  "Power" -> 0.0539598, "Rule" -> 0.0488813, "Blank" -> 0.0330909, 
  "Pattern" -> 0.0324028, "Slot" -> 0.0254302, 
  "CompoundExpression" -> 0.0214271, "Plus" -> 0.0213214|>

Not An Answer

---

Here's a cute way to look at what we like vs. what WRI likes:

symEnt[s_String] :=
  Entity["WolframLanguageSymbol", s];
symProp[cor_] :=
 EntityProperty["WolframLanguageSymbol", 
  "Frequencies", {"Corpus" -> cor}];
symClass[cor_ -> n_, props___] :=
 EntityClass[
  "WolframLanguageSymbol", {symProp[cor] -> TakeLargest[n], props}];
symClass[cor_ -> n_] :=

  EntityClass["WolframLanguageSymbol", symProp[cor] -> TakeLargest[n]];
symAssoc[e : _EntityClass | {__Entity}, cor_] :=

  KeyMap[CanonicalName]@
   EntityValue[e, symProp[cor], "EntityAssociation"];
symAssoc[cor_ -> n_] :=
 symAssoc[symClass[cor -> n], cor]

BarChart[likeRatio, 
 ChartLabels -> 
  Map[Rotate[Style[#, Bold, Black], Pi/2] &, Keys@likeRatio]]

Notably this suffers from lots of things with no DownValues but which are common return values.

More Precise Comparison

Perhaps more interesting is this comparison:

whatWeReallyLike =
  EntityValue["WolframLanguageSymbol", 
   EntityProperty["WolframLanguageSymbol", 
    "Ranks", {"Corpus" -> "StackExchange"}],
   "EntityAssociation"
   ];
whatWRIReallyLikes =
  EntityValue["WolframLanguageSymbol", 
   EntityProperty["WolframLanguageSymbol", 
    "Ranks", {"Corpus" -> "TypicalProductionCode"}],
   "EntityAssociation"
   ];
whatWRIReallyDocuments =
  EntityValue["WolframLanguageSymbol", 
   EntityProperty["WolframLanguageSymbol", 
    "Ranks", {"Corpus" -> "WolframDocumentation"}],
   "EntityAssociation"
   ];

What we really like:

whatWeReallyLike // TakeSmallest[25] // KeyMap[CanonicalName]

<|"List" -> 1, "Times" -> 2, "Set" -> 3, "Power" -> 4, "Rule" -> 5, 
 "Blank" -> 6, "Pattern" -> 7, "Slot" -> 8, "CompoundExpression" -> 9,
  "Plus" -> 10, "Part" -> 11, "Function" -> 12, "SetDelayed" -> 13, 
 "Equal" -> 14, "Map" -> 15, "Null" -> 16, "Pi" -> 17, 
 "ReplaceAll" -> 18, "Table" -> 19, "Sin" -> 20, "All" -> 21, 
 "Apply" -> 22, "Sqrt" -> 23, "True" -> 24, "Length" -> 25|>

What WRI really likes:

whatWRIReallyLikes // TakeSmallest[25] // KeyMap[CanonicalName]

<|"List" -> 1, "Times" -> 2, "Set" -> 3, "Power" -> 4, 
 "CompoundExpression" -> 5, "Plus" -> 6, "Rule" -> 7, "Null" -> 8, 
 "Pattern" -> 9, "Blank" -> 10, "Subscript" -> 11, "Part" -> 12, 
 "SetDelayed" -> 13, "HoldComplete" -> 15, "Print" -> 16, 
 "Slot" -> 17, "Equal" -> 18, "ReplaceAll" -> 19, "If" -> 20, 
 "Pi" -> 21, "False" -> 22, "Function" -> 23, "True" -> 24, 
 "MessageName" -> 25, "Table" -> 26|>

What we use more than WRI:

KeySelect[whatWeReallyLike - whatWRIReallyLikes, 
   whatWeReallyLike[#] <= 500 &] // TakeSmallest[10] // 
 KeyMap[CanonicalName]

<|"RepeatedTiming" -> -4490, "RightComposition" -> -1754, 
 "ArrayPad" -> -1680, "Query" -> -1431, "EdgeList" -> -1280, 
 "ComponentMeasurements" -> -1238, "VertexLabels" -> -1176, 
 "GatherBy" -> -1174, "Unitize" -> -1083, "GroupBy" -> -1057|>

What WRI uses more than us:

KeySelect[whatWeReallyLike - whatWRIReallyLikes, 
   whatWeReallyLike[#] <= 500 &] // TakeLargest[10] // 
 KeyMap[CanonicalName]

<|"ComplexExpand" -> 338, "Information" -> 319, 
 "NonCommutativeMultiply" -> 282, "Sinh" -> 258, "Message" -> 252, 
 "Italic" -> 248, "SelectionMove" -> 239, "Det" -> 236, 
 "Identity" -> 224, "Switch" -> 211|>

What WRI uses in its docs more than we use here:

KeySelect[whatWeReallyLike - whatWRIReallyDocuments, 
   whatWeReallyLike[#] <= 500 &] // TakeLargest[10] // 
 KeyMap[CanonicalName]

<|"Switch" -> 355, "DateListPlot" -> 325, "DateObject" -> 313, 
 "Histogram" -> 282, "Cuboid" -> 275, "ExampleData" -> 264, 
 "Distributed" -> 263, "Labeled" -> 260, "ContourPlot3D" -> 259, 
 "CountryData" -> 245|>

What we use in similar amounts:

KeySelect[whatWeReallyLike - whatWRIReallyLikes, 
   whatWeReallyLike[#] <= 250 &] // TakeSmallestBy[Abs, 25] // 
 KeyMap[CanonicalName]

<|"SetDelayed" -> 0, "Times" -> 0, "Power" -> 0, "Set" -> 0, 
 "List" -> 0, "True" -> 0, "Prepend" -> -1, "Mesh" -> 1, "Part" -> -1,
  "Unequal" -> 1, "ReplaceAll" -> -1, "Rule" -> -2, "Automatic" -> 2, 
 "Integrate" -> 2, "I" -> -2, "PatternTest" -> 2, "Cos" -> -2, 
 "Pattern" -> -2, "Integer" -> 3, "Blank" -> -4, "Equal" -> -4, 
 "Sqrt" -> -4, "Floor" -> -4, "Plus" -> 4, "Pi" -> -4|>

What WRI likes more than it documents:

KeySelect[whatWRIReallyLikes - whatWRIReallyDocuments, 
   whatWRIReallyDocuments[#] <= 500 && 
     whatWRIReallyLikes[#] <= 500 &] // TakeSmallest[10] // 
 KeyMap[CanonicalName]

<|"BlankNullSequence" -> -420, "MessageName" -> -420, 
 "Integer" -> -353, "AppendTo" -> -336, "Head" -> -331, 
 "AbsoluteThickness" -> -318, "Ticks" -> -310, "Bold" -> -309, 
 "PlotPoints" -> -309, "C" -> -305|>

What WRI documents more than it likes:

KeySelect[whatWRIReallyLikes - whatWRIReallyDocuments, 
   whatWRIReallyDocuments[#] <= 500 && 
     whatWRIReallyLikes[#] <= 500 &] // TakeLargest[10] // 
 KeyMap[CanonicalName]

<|"Hyperlink" -> 435, "Histogram" -> 393, "CDF" -> 380, 
 "Graph" -> 331, "PDF" -> 299, "Lighter" -> 296, "Sphere" -> 273, 
 "SeedRandom" -> 271, "Reduce" -> 260, "ColorData" -> 253|>