Here are some settings.future that I found.

Octal escape literal (has PR: scala/scala#6324)

https://github.com/scala/scala/blob/v2.13.0-M3/src/compiler/scala/tools/nsc/ast/parser/Scanners.scala#L874-L876

https://github.com/scala/scala/blob/v2.13.0-M3/src/compiler/scala/tools/reflect/FormatInterpolator.scala#L114-L118

scala> "\052"
<console>:12: warning: Octal escape literals are deprecated, use \u002a instead.
       "\052"
        ^
res0: String = *

Deprecated in 2.11. This should be removed in 2.13.

View bounds (has PR: scala/scala#6500)

https://github.com/scala/scala/blob/v2.13.0-M3/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala#L2424-L2426

https://github.com/scala/scala/blob/v2.13.0-M3/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala#L2873-L2874

Deprecated under -Xfuture. Should be deprecated in 2.13, and removed under -Xsource:2.14.

Procedure syntax (has PR: scala/scala#6325)

https://github.com/scala/scala/blob/v2.13.0-M3/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala#L2723-L2735

Deprecated under -Xfuture. Should be deprecated in 2.13, and removed under -Xsource:2.14.

Adaptation of nullary method (has PR: scala/scala#6797)

https://github.com/scala/scala/blob/v2.13.0-M3/src/compiler/scala/tools/nsc/typechecker/Adaptations.scala#L71-L88

See SI-7187 deprecate eta-expansion of zero-arg method values and Fix #2570: Part 3 - The great () insert.
See also scala/scala#6475.

This should be removed in 2.13.

Unsound type for ident/literal patterns (has PR: scala/scala#6502)

https://github.com/scala/scala/blob/v2.13.0-M3/src/compiler/scala/tools/nsc/transform/patmat/MatchAnalysis.scala#L37-L65

See SI-1503 don't assume unsound type for ident/literal patterns. Dotty currently has this test in pending https://github.com/lampepfl/dotty/blob/0.6.0-RC1/tests/pending/run/t1503.scala.

Dotty currently has this test in pending https://github.com/lampepfl/dotty/blob/0.6.0-RC1/tests/pending/run/t1503.scala.

The test hasn't been moved out of pending but Dotty now has the same behavior as scalac -Xfuture (see scala/scala3#4022)

Could someone add a progress bar to the ticket? :-) I think we're close to done on this, right?

Done. scala/scala#6475 didn't remove setting.future, so I don't think it qualifies as "has PR".