i3wm native split container guake-like dropdown terminal. The container drops down in animated steps using i3 move commands. In theory this could be extended to make any application dropdown summonable.

i3dropdown

#!/usr/bin/env python3
import i3ipc
from time import sleep

DROPDOWN_IDENTIFIER       = "dropdown"
DROPDOWN_CHILD_IDENTIFIER = "dropdownchild"
INITIAL_TERMINAL_QUANTITY = 3
TERMINAL_COMMAND          = f"terminal -n {DROPDOWN_CHILD_IDENTIFIER}"
HEIGHT_PERCENTAGE         = 39
FRAME_STEP                = 20
FRAME_DELAY               = 0.005


def is_ancestor(ancestor, descendent):
  ancestor_id = ancestor.id
  parent = descendent.parent
  while parent.type == 'con':
    if parent.id == ancestor_id: return True
    parent = parent.parent
  return False


def summon(dropdown, focused):
  workspace_rect = focused.workspace().rect
  dropdown_height = workspace_rect.height*HEIGHT_PERCENTAGE//100
  dropdown_width  = workspace_rect.width
  final_y = dropdown_height + workspace_rect.y
  move_cmd = f"move down {FRAME_STEP}px"
  dropdown.command(f"""scratchpad show,
                       resize set {dropdown_width} px {dropdown_height} px,
                       move absolute position {workspace_rect.x}px {-(dropdown_height-1)}px""")
  for i in range(1, final_y, FRAME_STEP):
    dropdown.command(move_cmd)
    sleep(FRAME_DELAY)
  dropdown.command(f"move absolute position {workspace_rect.x}px {workspace_rect.y}px, focus child")


def vanish(dropdown):
  dropdown_rect = dropdown.rect
  final_y = dropdown_rect.y + dropdown_rect.height
  move_cmd = f"move up {FRAME_STEP}px"
  for i in range(0, final_y, FRAME_STEP):
    dropdown.command(move_cmd)
    sleep(FRAME_DELAY)
  dropdown.command(f"move absolute position {dropdown_rect.x}px {-dropdown_rect.height}px")
  sleep(0.15)
  dropdown.command("move scratchpad")


i3 = i3ipc.Connection()
tree = i3.get_tree()
focused = tree.find_focused()

try:
  dropdown = tree.find_marked(DROPDOWN_IDENTIFIER)[0]
  if dropdown.workspace().id == focused.workspace().id:
    if is_ancestor(dropdown, focused):
      vanish(dropdown)
    else:
      dropdown.command('focus, focus child')
  else:
    summon(dropdown, focused)

except IndexError:
  # If we make it here, no container had the special dropdown mark.
  # i3 resets marks if it gets reloaded, so search for container whose instance name is identifier
  try:
    dropdown = tree.find_instanced(DROPDOWN_IDENTIFIER)[0].parent
    dropdown.command(f'mark --add {DROPDOWN_IDENTIFIER}')
    summon(dropdown, focused)

  except IndexError:

    # Last resort, spawn a new dropdown container with our terminals

    import subprocess
    import shlex
    import json
    import tempfile

    def terminal():   # Launch a background terminal process
      subprocess.Popen( shlex.split(TERMINAL_COMMAND),
                        shell=False,
                        stdin=None,
                        stdout=None,
                        stderr=None,
                        close_fds=True )


    terminal_placeholder = {
        "border": "pixel",
        "layout": "splith",
        "current_border_width": 1,
        "floating": "auto_off",
        "percent": 0.30,
        "swallows": [{ "instance": DROPDOWN_CHILD_IDENTIFIER }]
    }

    swallowable_layout = {
        "border":   "none",
        "floating": "auto_off",
        "layout":   "splith",
        "type":     "con",
        "name":     DROPDOWN_IDENTIFIER,
        "instance": DROPDOWN_IDENTIFIER,
        "marks":    [DROPDOWN_IDENTIFIER],
        "nodes":    [terminal_placeholder] * INITIAL_TERMINAL_QUANTITY
    }

    with tempfile.NamedTemporaryFile('w', delete=True) as f:
      f.write(json.dumps(swallowable_layout))
      f.flush()
      i3.command(f'append_layout {f.name}')

    tree = i3.get_tree()
    dropdown = tree.find_marked(DROPDOWN_IDENTIFIER)[0]
    dropdown.command("move scratchpad")
    for i in range(INITIAL_TERMINAL_QUANTITY):
      terminal()
    summon(dropdown, focused)