I want to the following events are available in the symbol palette: Conditional start event, Conditional Boundary event (non interrupting), Conditional intermediate catch event, Conditional Boundary event.

There are just regular StartEvent, Intermediate/Boundary Event, EndEvent.
That should be doable by creating a custom palette provider. Did you already check out the custom controls example?
Here is an example for creating a conditional start event
Source: custom palette provider (conditional start event) - CodeSandbox
getPaletteEntries() {
const create = this._create;
const elementFactory = this._elementFactory;
function createConditionalStartEvent(event) {
const shape = elementFactory.createShape({
type: "bpmn:StartEvent",
eventDefinitionType: "bpmn:ConditionalEventDefinition"
});
create.start(event, shape);
}
return function (entries) {
// add conditional start event
entries["create.conditional-start-event"] = {
group: "event",
className: "bpmn-icon-start-event-condition",
title: "Create Conditional Start Event",
action: {
dragstart: createConditionalStartEvent,
click: createConditionalStartEvent
}
};
return entries;
};
}
@Niklas_Kiefer thank you so much!
@Niklas_Kiefer I implemented “conditional boundary event (non interrupting)” and “conditional intermediate catch event” based on example above. custom palette provider (conditional start event) (forked) - CodeSandbox
I am interested is it good implementation? and where are used properties of entries object and how is important their naming? I think on “create.conditional-intermediate-event” and “create.conditional-intermediate-catch-event”.