Store all class names for runtime use.

ClassList.hx

package ;

#if macro
import haxe.macro.Context.*;
using haxe.macro.Tools;
#end

class ClassList {
  static var NAME = 'ClassList';//must be the fully qualified name of this class
  macro static function build() {
    onGenerate(function (types) {
      var names = [],
          self = getType(NAME).getClass();
      for (t in types)
        switch t {
          case TInst(_.get() => c, _):
            names.push(makeExpr(c.name, c.pos));
          default:
        }
        
      self.meta.remove('classes');
      self.meta.add('classes', names, self.pos);
    });
    return macro cast haxe.rtti.Meta.getType($p{NAME.split('.')});
  }
  #if !macro
  static public var ALL_NAMES(default, null):Array<String> = build();
  #end
}

Usage.hx

package ;

class Usage {
  static function main() {
    trace(ClassList.ALL_NAMES);
  }
}