flutter-quill/doc/custom_toolbar.md

Custom Toolbar

If you want to use a custom toolbar but still want the support of this library, You can use the QuillBaseToolbar which is the base for the QuillToolbar

Example:

QuillToolbar.simple(
  configurations: const QuillSimpleToolbarConfigurations(
    buttonOptions: QuillToolbarButtonOptions(
      base: QuillToolbarBaseButtonOptions(
        globalIconSize: 20,
        globalIconButtonFactor: 1.4,
      ),
    ),
  ),
  child: SingleChildScrollView(
    scrollDirection: Axis.horizontal,
    child: Row(
      children: [
        IconButton(
          onPressed: () => context
              .read<SettingsCubit>()
              .updateSettings(
                  state.copyWith(useCustomQuillToolbar: false)),
          icon: const Icon(
            Icons.width_normal,
          ),
        ),
        QuillToolbarHistoryButton(
          isUndo: true,
          controller: controller,
        ),
        QuillToolbarHistoryButton(
          isUndo: false,
          controller: controller,
        ),
        QuillToolbarToggleStyleButton(
          options: const QuillToolbarToggleStyleButtonOptions(),
          controller: controller,
          attribute: Attribute.bold,
        ),
        QuillToolbarToggleStyleButton(
          options: const QuillToolbarToggleStyleButtonOptions(),
          controller: controller,
          attribute: Attribute.italic,
        ),
        QuillToolbarToggleStyleButton(
          controller: controller,
          attribute: Attribute.underline,
        ),
        QuillToolbarClearFormatButton(
          controller: controller,
        ),
        const VerticalDivider(),
        QuillToolbarImageButton(
          controller: controller,
        ),
        QuillToolbarCameraButton(
          controller: controller,
        ),
        QuillToolbarVideoButton(
          controller: controller,
        ),
        const VerticalDivider(),
        QuillToolbarColorButton(
          controller: controller,
          isBackground: false,
        ),
        QuillToolbarColorButton(
          controller: controller,
          isBackground: true,
        ),
        const VerticalDivider(),
        // This is an implementation that only is used on
        // flutter_quill and it's not originally 
        // implemented in Quill JS API, so it could cause conflicts
        // with the original Quill Delta format
        QuillToolbarSelectLineHeightStyleDropdownButton(
          controller: globalController,
        ),
        const VerticalDivider(),
        QuillToolbarSelectHeaderStyleButton(
          controller: controller,
        ),
        const VerticalDivider(),
        QuillToolbarToggleCheckListButton(
          controller: controller,
        ),
        QuillToolbarToggleStyleButton(
          controller: controller,
          attribute: Attribute.ol,
        ),
        QuillToolbarToggleStyleButton(
          controller: controller,
          attribute: Attribute.ul,
        ),
        QuillToolbarToggleStyleButton(
          controller: controller,
          attribute: Attribute.inlineCode,
        ),
        QuillToolbarToggleStyleButton(
          controller: controller,
          attribute: Attribute.blockQuote,
        ),
        QuillToolbarIndentButton(
          controller: controller,
          isIncrease: true,
        ),
        QuillToolbarIndentButton(
          controller: controller,
          isIncrease: false,
        ),
        const VerticalDivider(),
        QuillToolbarLinkStyleButton(controller: controller),
      ],
    ),
  ),
)

if you want a more customized toolbar feel free to create your own and use the controller to interact with the editor. checkout the QuillToolbar and the buttons inside it to see an example of how that will work