Based on myknowledge, it’s not feasible to export lists and libraries in SharePoint Online using PowerShell.
For detailed information about the cmdlets for SharePoint Online, please see:
Introduction to the SharePoint Online Management Shell.
Basically using CSOM you can create lists using already existing custom templates, but programmatically you cannot create new ones as SaveAsTemplate method is not exposed in CSOM API.
To create a list from existing custom template below is the code.
ClientContext context = new ClientContext("http://SiteUrl");
var web = context.Web;
context.Load(web,s => s.ListTemplates );
context.ExecuteQuery();
var listCreationInfo = new ListCreationInformation
{
Title = "My Jobs",
Description = "This is the job list description"
};
var listTemplate = site.ListTemplates.First(template => template.Name == "Jobs");
listCreationInfo.TemplateFeatureId = listTemplate.FeatureId;
listCreationInfo.TemplateType = listTemplate.ListTemplateTypeKind;
site.Lists.Add(listCreationInfo);
context.ExecuteQuery();