You can choose whatever suitable topic you prefer, but please mind the following points: 

• Target Audience - Your audience will be composed of developers, system admins, end users and business users.
• Share Latest Features - Attendees are looking how the latest announcements from Microsoft Ignite 2018 impact their day to day. Make sure your title and description call out specifics on what users can expect.
• Connect and Network - if possible, no "parachuting". We expect you to be here for the whole Saturday and mingle with the attendees during the SharePint. We appreciate that you are spending time away from family and personal commitments so try to engage the event, network with attendees, speakers and sponsors. 
• Inspire rather then sell - we all love what we do.  Try not promote yourself too much. We're sure that your company or product are the best, but we don't allow marketing sessions (they are reserved for our sponsors and clearly separated in the agenda). Of course, you can refer to your company in your talk but you know the line. Thank you for respecting it.
• Diversity & Inclusion - we are dedicated to providing a harassment-free conference experience for everyone, regardless of gender, sexual orientation, disability, physical appearance, body size, race, or religion. We do not tolerate harassment of participants in any form. All communication should be appropriate for a professional audience including people of many different backgrounds. Sexual language and imagery is not appropriate for any conference venue, including talks. Be kind to others. Do not insult or put down other attendees. Behave professionally. Remember that harassment and sexist, racist, or exclusionary jokes are not appropriate.