I have noticed other ISO standards available, should I be working towards these as well?

One of the aims of ISO 9001:2015 is to ensure that it is easily compatible with other ISO standards available. Commonly compatible standards include ISO 14001:2015 which specifies the requirements for an organisation's environmental management system. It is your decision as to how compatible and relevant other standards are to your organisation, however as with ISO 9001:2015 the internal and external rewards from becoming accredited are high.